Roundtable 8-3 on Theory of Unipolar Politics

Theory of Unipolar Politics coverHow long will the United States remain the world’s sole superpower, uniquely capable of commanding the commons and projecting sustained military power to overseas regions? Why has the United States been so prone to use military force in the years since the Soviet Union collapsed? And how might answers to these questions hinge on strategic choices made in Washington?   These are the questions Nuno Monteiro set out to answer in his rigorously argued Theory of Unipolar Politics. They have been at the center of intense debates for a quarter century—and not just in the ivory tower but also among pundits, politicians, intelligence analysts, policymakers and even leaders of major powers.   Monteiro’s arguments have attracted a lot of attention, and deservedly so. Not only does he develop them with great care and express them in clear, forceful prose, he does not shrink from tackling tough problems. In contrast to Kenneth Waltz’s seminal Theory of International Politics,[1] for example, Monteiro’s book deals head on with the interaction between strategic choice and systemic outcomes and the influence of nuclear deterrence on classical balance-of-power thinking.

H-Diplo | ISSF Roundtable, Volume VIII, No. 3 (2015)

H-Diplo/ISSF Editors: James McAllister and Diane Labrosse
H-Diplo/ISSF Roundtable and Web/Production Editor: George Fujii
Commissioned for H-Diplo/ISSF by James McAllister
Introduction by William C. Wohlforth

Nuno P. Monteiro. Theory of Unipolar Politics. Cambridge University Press, 2014. ISBN:   9781107677753 (paperback, $28.99); 9781107061804 (hardback, $85.00).

Published by H-Diplo/ISSF on 12 October 2015

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Contents

Introduction by William C. Wohlforth, Dartmouth College

How long will the United States remain the world’s sole superpower, uniquely capable of commanding the commons and projecting sustained military power to overseas regions? Why has the United States been so prone to use military force in the years since the Soviet Union collapsed? And how might answers to these questions hinge on strategic choices made in Washington?   These are the questions Nuno Monteiro set out to answer in his rigorously argued Theory of Unipolar Politics. They have been at the center of intense debates for a quarter century—and not just in the ivory tower but also among pundits, politicians, intelligence analysts, policymakers and even leaders of major powers.   Monteiro’s arguments have attracted a lot of attention, and deservedly so. Not only does he develop them with great care and express them in clear, forceful prose, he does not shrink from tackling tough problems. In contrast to Kenneth Waltz’s seminal Theory of International Politics,[1] for example, Monteiro’s book deals head on with the interaction between strategic choice and systemic outcomes and the influence of nuclear deterrence on classical balance-of-power thinking.

One measure of a book’s quality is the quality of the responses it generates. By that metric Monteiro has every reason to be pleased. Christopher Layne is arguably unipolarity’s first scholarly theorist, having set forth the definitive balance-of-power realist assessment in 1993, well before Waltz himself got around to it in 2000.[2] (Indeed, in 1993 Waltz was still discussing the system’s structure as “altered bipolarity”[3]). In the years since, Layne has developed and defended this argument in a series of highly cited contributions marked by his signature deep engagement with historical evidence and trenchant criticisms of U.S. grand strategy. Here he does not disappoint, taking on nearly every core contention in Monteiro’s book. Jeffrey Taliaferro is one of this country’s leading realist scholars and students of U.S foreign policy. His review neatly assesses Montero’s contribution, places it in its theoretical context, and raises some important questions about its key claims. Michael Beckley is the author of cutting edge research on the United States’ position in the international system, the nature and limits of China’s rise, and the costs and benefits of US grand strategy.[4] He joins the others in praising Theory of Unipolar Politics but wastes no time before zeroing with trenchant criticisms of three core assumptions that undergird the book. For those who have not read Monteiro’s book or his other works, the high quality of his response will help you understand why Theory of Unipolar Politics has stimulated such a productive debate. It is a spirited but carefully argued rebuttal that leaves almost no criticism unaddressed. It helpfully clarifies claims, establishes where the true disagreements lie, and suggests what can and cannot be resolved by empirical research.

My job is to introduce this exchange, not participate in it or attempt to adjudicate it. For those who have not yet read Monteiro’s book, the best way to read this exchange is to skip ahead and start with Monteiro’s own recapitulation of its main arguments, and then read the reviews in order and return to the rest of Monteiro’s response. This forum will make for engaging and instructive reading, regardless of whether readers are deeply immersed in the literature.

Participants:

Nuno P. Monteiro is Associate Professor of political science at Yale University, where he is also director of graduate studies at the Jackson Institute for Global Affairs and a Research Fellow at the Whitney and Betty MacMillan Center for International and Area Studies. He is interested in international relations theory and security, with an emphasis on great-power politics, the politics of the nuclear age, the causes of war, military power, deterrence theory, political violence, and the philosophy of science. He is the author of Theory of Unipolar Politics (Cambridge University Press, 2014) and Nuclear Politics: The Strategic Logic of Proliferation (with Alexandre Debs, Cambridge University Press, forthcoming), as well as articles published in International Organization, International Security, and International Theory. He received his Ph.D. from the University of Chicago in 2009.

William C. Wohlforth is the Daniel Webster Professor of Government at Dartmouth College. He is the author or editor of eight books and some 60 articles and book chapters on topics ranging from the Cold War and its end to status in world politics, unipolarity, and contemporary U.S. grand strategy. He has held fellowships at the Institute of Strategic Studies at Yale, the Center for International Security and Cooperation at Stanford, and the Hoover Institution.  He is a member of the Council of Foreign Relations and has served as a consultant for the National Intelligence Council and the National Bureau of Asian Research.  His most recent books are Status and World Order (Cambridge 2014), edited with T.V. Paul and Deborah Larson, and America Abroad: The United States’ Global Role in the 21st Century (forthcoming, Oxford), with Stephen Brooks.

Michael Beckley is an Assistant Professor of Political Science at Tufts University.  His research focuses on national power, unipolarity, and U.S. and Chinese foreign policy and has been featured in a variety of academic journals and media including International Security, Foreign Policy, The National Interest, National Public Radio, The Washington Post, The Financial Times, and The Journal of Strategic Studies, which awarded him the Amos Perlmutter Prize for best article of the year.  Prior to Tufts, he was a fellow at Harvard’s Kennedy School and Dartmouth College and worked at the U.S. Department of Defense, the RAND Corporation, and the Carnegie Endowment for International Peace.

Christopher Layne is a University Distinguished Professor, Robert M. Gates Chair in National Security, and professor of international affairs at the Bush School of Government and Public Service at Texas A&M University. His fields of interest are international relations theory, great power politics, US foreign policy, and grand strategy. Professor Layne has written two books: The Peace of Illusions: American Grand Strategy from 1940 to the Present (Cornell University Press, 2006), and (with Bradley A. Thayer) American Empire: A Debate (Routledge, 2006). His current book project, After the Fall: International Politics, U.S. Grand Strategy, and the End of the Pax Americana, is under contract with Yale University Press. During summer 2014, he was a Visiting Fellow at the Norwegian Nobel Institute.

Jeffrey W. Taliaferro is an Associate Professor of Political Science at Tufts University, where he has taught since 1997. His research and teaching focus on security studies, international relations theory, international history and politics, and United States foreign policy. Taliaferro is the author of Balancing Risks: Great Power Intervention in the Periphery (Cornell University Press, 2004), which won the American Political Science Association’s Robert L. Jervis and Paul W. Schroeder Award for the Best Book in International History and Politics. His articles have appeared in International Security, Security Studies, and Political Psychology and several edited volumes. He is co-editor, along with Steven E. Lobell and Norrin P. Ripsman, of Neoclassical Realism, the State, and Foreign Policy (Cambridge University Press, 2009) and of The Challenge of Grand Strategy: The Great Powers and the Broken Balance between the World Wars (Cambridge University Press, 2012).

Review by Michael Beckley, Tufts University

Nuno Monteiro has written a brilliant theory that will shape debates on unipolarity for years to come. The theory, however, makes two faulty assumptions: first, that rising economic powers with nuclear weapons will not seek to become military powers; and second, that unipolarity generates unique commitment problems between great and minor powers. As a result, Monteiro’s theory may underestimate the impact that China’s economic rise would have on the international system and overestimate the likelihood of wars between the United States and recalcitrant minor powers.

Regarding China’s rise, Monteiro’s theory assumes that states are security-satisfiers rather than power-maximizers. It further assumes that states need only two things to feel secure: a nuclear deterrent and decent economic growth prospects. Based on these assumptions, Monteiro predicts that China will not militarize, even if it becomes an economic superpower, as long as the United States refrains from containing Chinese economic growth or extending U.S. military dominance in East Asia.

Are these assumptions sound? And do they support Monteiro’s rosy prediction about the rise of China? Unfortunately not.

For starters, Monteiro’s assumption that states seek only basic survival is really a hypothesis that remains to be demonstrated, and contradicts the traditional realist view that states’ ambitions grow as their material resources expand.[5] Rising economic powers may not expand militarily in a mad frenzy, but history suggests they will do so in a calculated manner in places and at times that minimize costs and risks.

Monteiro claims that two factors dull this expansionist impulse in China’s case. First, he argues that the nuclear revolution allows China to ensure its survival with a small nuclear arsenal and, therefore, to forgo militarization. If nuclear deterrence is as solid as Monteiro claims, however, then the world is safe for conventional war. As Avery Goldstein points out, Chinese leaders “apparently believe that nuclear deterrence opens the door to the safe use of conventional force” and are investing heavily in capabilities that would enable China to strike first and win short, sharp conventional wars.[6] Perhaps nuclear weapons will keep the lid on major conflicts. The history of Cold-War crises, arms races, and proxy wars, however, shows that Mutual Assured Destruction (MAD) does not guarantee military restraint.

Second, Monteiro claims that China will refrain from militarization as long as the United States sticks to its status quo strategy of “defensive accommodation.” This argument errs, however, not only in assuming that Chinese militarization depends solely on the actions of the United States, but also in assuming that China is satisfied with the status quo. In fact, Chinese leaders have made clear that they aim to eliminate, by force if necessary, several features of the status quo, including Taiwan’s quasi-independent status, the claims of a half-dozen countries on chunks of territory that China regards as its own, the ring of military alliances surrounding China’s coastline, and threats to China’s access to vital resources, most of which are imported from outside Asia and pass through choke-points dominated by potentially hostile countries. China is unlikely to abandon these goals just because the United States maintains a “defensive” posture, especially when that posture is based on a massive U.S. military presence in China’s backyard.

Indeed, there is substantial evidence that China aims to bolster its military capabilities and eventually redraw the geopolitical map. Monteiro makes much of the fact that China’s defense spending has remained pegged at two percent of GDP for decades, but this point seems trivial given China’s rapid economic growth during that time. The fact is that over the last decade China has increased its defense budget 170 percent and made notable, albeit limited, investments in power-projection capabilities.[7] Moreover, during the last five years China has extended its baseline claims and established an Air Defense Identification Zone over the East China Sea, occupied contested features and established a prefectural government on a disputed island in the South China Sea, and ramped up its maritime, air, and ground patrols in and around disputed territories. These actions may not place China in the same league as the Soviet Union or Imperial Germany, but they do resemble actions taken by the United States in the late nineteenth century, when it expelled other great powers from the Western Hemisphere and established its status as a regional hegemon, all while keeping defense spending at one percent of GDP.

According to Monteiro, China’s assertive actions in Asia and development of anti-access/area-denial capabilities can be dismissed as regional issues that do not affect the durability of unipolarity.   This claim, however, is debatable.   After all, Asia accounts for 60 percent of the world’s population, 20 percent of global GDP, and 25 percent of world defense spending. Surely China’s efforts to undercut U.S. influence there have significant implications for unipolar durability, if for no other reason that Chinese hegemony in Asia would facilitate Chinese power-projection outside of Asia. As Evan Montgomery argues, defining balancing solely in terms of power-projection, as Monteiro does, is problematic because it assumes that local balancing is unrelated to global balancing.[8] In reality, challenging U.S. influence in Asia and balancing U.S. power globally are overlapping objectives. The bulk of the evidence suggests that China has already started to pursue both goals. If China closes the economic gap with the United States in the decades ahead, expect it to redouble its efforts.

The other questionable assumption in Monteiro’s theory has to do with conflict between the unipole and minor powers. According to Monteiro, unipolarity encourages recalcitrant minor powers to acquire nuclear weapons. The unipole, of course, wants to prevent nuclear proliferation. These competing goals not only create a conflict of interest between the unipole and minor powers, but also undermine their ability to reassure one another. Minor powers cannot credibly commit not to develop nuclear weapons, and the unipole cannot credibly commit not to attack minor powers. As a result, “unipolarity generates conditions propitious for significant conflict” (5).

No doubt, these commitment problems are serious, but are they “unique to a unipolar world,” (15) as Monteiro asserts? The available evidence suggests not.

First, minor powers have strong incentives to acquire nuclear weapons regardless of the global distribution of power. In fact, the literature on nuclear proliferation shows that countries seek nuclear weapons primarily to counter local threats that exist independent of the polarity of the system.[9]

Monteiro’s theory assumes that minor powers in bipolar or multipolar systems can credibly commit not to acquire nuclear weapons by acquiring great power allies. As the history of the Cold War shows, however, only some minor powers receive security guarantees from great powers, and most of those that do still develop, or at least consider developing, nuclear capabilities because they fear that their great power protector will ultimately abandon them.

Perhaps Monteiro is correct that unipolarity fuels proliferation incentives, but this claim confronts an inconvenient fact:   no nation has started a new nuclear weapons program since the emergence of unipolarity in 1991. Every country that has ever acquired, or sought to acquire, nuclear weapons, including all of the recalcitrant minor powers that Monteiro highlights, began their efforts under bipolarity. Not surprisingly, American fears of minor-power proliferation were pronounced throughout the Cold War, perhaps more so than they are today.

Second, it is not clear that unipolarity uniquely undermines a great power’s ability to reassure minor powers. True, the absence of a great power competitor theoretically unleashes the unipole to attack minor powers. The absence of geopolitical competition, however, also eliminates one of the chief reasons why a great power would intervene in the periphery in the first place.

In bipolar or multipolar systems, there are no peripheries; anything that happens anywhere in the world has potential implications for great-power politics. Under such conditions, recalcitrant minor powers become logical targets because their insubordination threatens the prestige and credibility, if not the security, of their great power enemies.

Under unipolarity, by contrast, recalcitrant minor powers are minor players. They can threaten the unipole, but unipolarity prevents these threats from assuming great power proportions. Thus, a unipole may be able to credibly commit not to attack minor powers, despite the large power gap between them, because of its manifest lack of interest in going to war over minimal stakes.

Of course, powerful states will still have trouble committing not to attack weaker enemies, but it seems strange to argue, as Monteiro does, that this commitment problem is “characteristic of a unipolar system” (146) given that the United States and the Soviet Union routinely clashed with minor powers during the Cold War.

Thus, the commitment problems that Monteiro highlights are primarily dyadic, rather than systemic, phenomena. Minor powers facing a powerful enemy have clear incentives to acquire nuclear weapons regardless of the global distribution of power, and great powers will always have trouble credibly committing not to attack recalcitrant minor powers. Under unipolarity, the United States is more capable of attacking minor powers, but it also has fewer interests in doing so. Monteiro’s theory focuses on the former while neglecting the latter; in other words, it focuses on the unipole’s superior capabilities while neglecting the unipole’s attenuated resolve. As a result, Monteiro’s theory may overstate the extent to which unipolarity generates commitment problems between great and minor powers and, consequently, may overestimate the amount of conflict we can expect to see in a unipolar world.

Review by Christopher Layne, Texas A & M University

In Theory of Unipolar Politics, Yale assistant professor Nuno P. Monteiro aims to fill what he sees as a gap in the extant International Relations (IR) theory literature. As he sees it, while some of the features of unipolarity have been addressed intuitively, they “have never been treated systematically in the context of an integrated theory that lays out the connections between these issues” (16). “Simply put,” he writes , “there is not much theoretical literature exploring the workings of unipolarity, neither in the abstract nor in relation to our historical experience since the end of the Cold War” (16).[10] Monteiro sees his book as following in the footsteps of Kenneth Waltz’s Theory of International Politics.[11]

The Soviet Union’s collapse, of course, transformed the post-World War II international system from bipolarity to unipolarity. Since the Cold War’s end, ‘unipolarity’ has had a double meaning. First, it is (or, perhaps, was) an objective description of the distribution of power in the post-1991 international system. Second, the maintenance of the United States’ position as the sole great power (unipole) in international politics has been the bedrock aim of its grand strategy since the early 1990s.[12] Unipolarity has been the topic of intense debate among IR scholars. Leading balance-of-power realists predicted that unipolarity would give way within an a reasonably short time to a restored (bipolar or multipolar) balance of power.[13] This view was challenged by the advocates of “unipolar stability” who proclaimed that unipolarity would last for a very long time.[14] In other words, the debate between these two camps was about the prospective durability of a unipolar world. Parallel to this IR theory debate, there has been a closely related – and lively – debate about whether the perpetuation of unipolarity is the optimal grand strategy for the United States.[15]

Monteiro engages these debates full-on. He addresses what he believes are the three most important questions about unipolarity. First, is unipolarity durable? Second, is unipolarity peaceful? Finally, what is the best grand strategy for a unipole (read: the United States)? Here, Monteiro shows how the unipole’s choice of grand strategy affects the durability and peacefulness of a unipolar system. These are important questions, and Monteiro deserves credit for trying to think through the implications of unipolarity in a systematic fashion. Whether his answers are convincing, however, is another matter.

Monteiro’s starting point – shared with primacist scholars like Stephen Brooks and William C. Wohlforth – is that the current international system is unipolar. Like Brooks and Wohlforth, he believes it is likely to remain so. These contentions are problematic, and a topic to which I will return below. Monteiro opens the book by describing what he sees as U.S. global military preponderance (what the Pentagon likes to call ‘full spectrum dominance’). He argues that the U.S. is far ahead of any possible challenger in all forms of military power (1-3). Moreover, he suggests, because of U.S. technological supremacy, America’s military advantage is likely to increase in coming decades. As a result of its military prowess, the United States commands the global commons, and is the only state in the international system with the capability to project military power to all regions of the globe.[16] Thus, he says, “Since the fall of the Soviet Union…the United States has been the world’s sole great power. We live in a unipolar world” (3). In the remainder of the book he lays out the causal logic that purports to support his argument.

The argument presented in Theory of Unipolar Politics is complex, and touches upon many aspects of IR theory and grand strategy. Rather than critiquing every aspect of Monteiro’s argument, I will focus on five key points. First, I dissect Monteiro’s argument for the durability of unipolarity. Second, I address his claims about the peacefulness of unipolar systems. Third, I ask whether Monteiro’s assessment of U.S. strategic options in a unipolar system is correct. Fourth, I show why Monteiro’s assertion that the present international system is unipolar is off-base. In so doing, I also show why his analysis of the evolving Sino-American relationship rests on a shaky foundation.

Since the beginning of the Unipolar Era, American IR/security scholars have basically divided into two camps on the question of whether the unipolar system is durable: optimists, and pessimists. In the immediate aftermath of the Cold War, balance-of-power realists argued that unipolarity would be a short-lived transitional phase from bipolarity to multipolarity.[17] Unipolarity, they said, would spur the emergence of new great powers to act as counterweights to U.S. hegemony. These ‘unipolar pessimists’ also questioned the wisdom of making the preservation of U.S. dominance in a unipolar world the overriding goal of the United States’ post-Cold War grand strategy. Pointing to a long historical record, they demonstrated that failure is the fate of states that attempt to dominate the international system. The bids for geopolitical preponderance of the Habsburgs (under Charles V and Philip II), France (under Louis XIV and Napoleon I), and Germany (under Wilhelm II and Adolph Hitler) all were defeated by the resistance of countervailing alliances, and by the consequences of their own strategic over-extension. In a unipolar world, they argue, the U.S. would not be immune from this pattern. ‘Unipolar optimists’ in the primacist camp, on the other hand, maintain that the U.S. will buck the historical trend of failure by powers seeking dominance because the magnitude of U.S. power precludes other states from balancing against the United States’ hegemony. Simply put, they believe the military and economic power gap between the U.S. and its nearest rivals is insurmountable – so wide that no state can hope to close it.[18] Monteiro claims his theory offers a way of breaking the impasse between unipolar optimists and unipolar pessimists. Each side, he says, has useful insights. But in his estimation, both sides miss a fundamental point: the durability of a unipolar world is conditional. Monteiro suggests unipolar durability “depends on two variables: one systemic and one strategic” (79). When these two variables, the nuclear revolution and the unipole’s grand strategy, align correctly, potential great powers in a unipolar system will not seek to become peer competitors of the unipole. Thus, he believes that unipolarity is “potentially durable” (4).

The logic underpinning this conclusion proceeds from one of his foundational assumptions: that “states care first and foremost about survival” (13). Balance-of-power realists, of course, agree. Both they and Monteiro concur that to ensure their survival and security, states build up their own military capabilities to checkmate states that seek to dominate the system, and thereby preserve a systemic balance of power. At this point, however, Monteiro and balance-of-power realists part ways. Distilled to its essence, Monteiro’s argument asserts that the nuclear revolution has made unipolarity robust.[19] As he argues, “the nuclear revolution is a condition of a possibility of a durable nuclear world” (50). The nuclear revolution, he states, is an “integral component” of his theory (50). He goes on to say that absent the nuclear revolution, “there would be no need for the theory [of unipolar politics]; a unipolar world would quickly disappear, turning any inquiry into its propensity for peace and the constraints it imposes on strategy into an otiose academic exercise” (50). Clearly, the nuclear revolution (or his understanding of it) does most of the heavy lifting in Monteiro’s theory of unipolar politics.

In contrast to balance-of-power realists, Monteiro believes that the nuclear revolution negates the balancing dynamics that historically have driven great powers’ grand strategies, and characterized international political behavior.[20] Balancing behavior to counter a state’s drive to dominate the international system is something that only happens in a non-nuclear – that is, conventional weapons – world. This is because the nuclear revolution has two important effects. First, for states that have a secure, second-strike retaliatory capability, nuclear weapons guarantee survival.[21] Hence, according to Monteiro, unlike in a conventional world, in a nuclear unipolar world there no need for the major powers to try to offset (balance) the unipole’s power preponderance, because nuclear weapons have rendered irrelevant the distribution of power in the international system. As he notes, “Because the ability of a nuclear state to inflict high costs on the enemy does not depend on a balance of conventional power, a nuclear power may deter any state – even one significantly more powerful in conventional terms – from threatening its survival” (90). With their own survival assured, major powers have no incentive to risk conflict with the unipole by balancing against it.

The nuclear revolution’s second big effect, according to Monteiro, is that nuclear weapons critically affect the strategic calculus of the major powers. In a non-nuclear world, concern for survival and security (and other imperatives) might drive one or more of the major powers to challenge the unipole, and attempt to restore a power balance in the international system – just as in a multipolar system where great powers balance against states that seek dominance. In a conventional world, the decision to challenge a dominant state depends on the trade-off between the expected costs of a possible conflict weighed against the possible gains.[22] In a nuclear world, however, major powers will not attempt to restore a systemic balance-of-power by challenging the unipole militarily because “the expected costs of great power war are terrifically high” (4).[23]

Nuclear weapons are the necessary condition for unipolar durability. But, by themselves, according to Monteiro, they are not sufficient to ensure unipolarity’s durability. To ensure the continuation of unipolarity, the unipole must follow a grand strategy of what he calls “defensive dominance” (4).[24] This means that the unipole must accommodate the economic growth of the rising powers by avoiding any attempt to constrict or limit their growth.[25] Militarily, defensive accommodation requires that the unipole must maintain the existing geopolitical status quo in the regions where major powers or located (100-101). That is, the unipole must “refrain from attempting to extend its military dominance in their region, because this might threaten their long term economic viability” (4).[26] The unipole must also accommodate the economic growth of rising powers. “The durability of a unipolar world,” Monteiro asserts, “requires that the unipole eschew any actions directed at containing major powers’ economic growth, such as disrupting or limiting the flows of trade, investment, raw materials, and so on” (100). On the other hand, according to Monteiro, major powers they will challenge a unipole pursuing an offensive dominance strategy. As he writes, if “the unipole implements a strategy that threatens to contain the economic growth of rising powers, then those other states have greater incentives to invest in additional military capabilities beyond those that assure their immediate security and survival, thereby putting up a military challenge to the unipole…rising powers in a unipolar world may continue to convert their growing latent power into military power beyond the point at which their survival is guaranteed by a nuclear deterrent…” (4-5).

Monteiro’s claim that unipolarity is durable is complex, and consists of a number of claims that are tightly interwoven. But if one begins to pull on any one of several threads, the entire fabric of his argument for unipolar durability become problematic. A good place to start unraveling Monteiro’s claim for unipolar durability is with his assumption that the fundamental motivation of states is survival. Obviously, states care about their survival. Monteiro, however, seems to believe that survival is an end in itself. Hence his claim that once the other major powers acquire survivable nuclear deterrent capabilities, they will not balance against the unipole. (Unless, of course, the unipole follows an offensive dominance grand strategy – an assertion that, as we shall see, has its own problems). Monteiro misses an important point: for states, survival is not an end, it is a means to other ends. As Kenneth Waltz said, “Only if survival is assured can states safely seek such other goals as tranquility, profit, and power.”[27]

Even when their survival is assured, the pursuit of other objectives can cause security competitions, and even war. The run-up to World War I is illustrative. In the years before August 1914, neither Germany nor Britain threatened the other’s survival. But they engaged in an intense security competition that contributed importantly to the outbreak of the Great War. In addition to power and security they also wanted status and prestige.[28] As Michelle Murray notes, “in addition to physical security, states also want recognition, and this process of securing an identity can give rise to an array of material risks that have traditionally characterized great power politics.”[29] Along with the acquisition of colonies, the construction of Germany’s ‘luxury fleet’ (as First Lord of the Admiralty Winston Churchill described it) was part of Berlin’s strategy to gain equal status with London in the international system and to match Britain in prestige. Germany built battleships because they “were understood at the time to be emblematic of great power status.”[30] As Annika Mombauer observes, “in Germany it was felt that the country deserved to play a greater role and to have a ‘place in the sun,’ for which a powerful navy was portrayed as an essential prerequisite.”[31] German Chancellor Theobald von Bethmann Hollweg asserted that to be a “really Great Power” Germany “must have a fleet, and a strong one…not merely for the purposed of defending her commerce but for the general purpose of her greatness.”[32] Writing in the midst of the war in 1916, the renowned German military historian Otto Hintze clearly spelled out the considerations of status and prestige that drove Germany’s pre-1914 naval build-up:

Our intention was to develop gradually in peaceful competition with England, until the older power would one day be forced to recognize as an equal competitor in world politics.   England is still far from granting any such equality to the continental powers, and the German refusal to admit England’s sole supremacy at sea was certainly the main cause that drove the island kingdom into a war with Germany. Our aim in this war can only be to force England to abandon her claims to absolute supremacy at sea and thus to create a state of equilibrium with the world system of states.[33]

It was Germany’s desire to be recognized as Britain’s equal that ramped-up the intensity of the Anglo-German rivalry. Because they are positional goods, the competition for status and prestige tends to be zero sum.[34] Status inconsistency – the disjuncture between the what Robert Gilpin calls the international system’s hierarchy of prestige and the underlying distribution of power – is a potent generator of conflict as rising powers strive to reshape the international system to reflect – and gain recognition of – their rising power.[35]

Monteiro’s claims notwithstanding, even in a nuclear unipolar world the quest for wealth, power, and status will generate military competitions between rising powers and the unipole. The theory of unipolar stability reflects a shaky grasp of nuclear strategy. Nuclear weapons indeed are fearsome in their potential destructiveness. But this does not lead to the conclusion that a survivable deterrent automatically guarantees the survival of their possessors. For sure there are those who believe, as did the late Robert S. McNamara, that “nuclear weapons serve no useful military purpose whatsoever. They are totally useless – except to deter one’s opponent from using them.”[36] Nevertheless, throughout the Cold War, U.S. strategists devoted considerable time to thinking about the possibilities of nuclear war-fighting, limited nuclear war, limited nuclear options, escalation dominance, the impact of new generations of low-yield nuclear weapons married to highly accurate delivery systems, and the use of nuclear weapons as coercive instruments of diplomacy.[37] Within the Pentagon, these ideas are still taken seriously, and one presumes that nuclear powers like Russia and China similarly think along these lines.

In light of historical experience, it also is far from clear that Monteiro is correct in claiming that, in a unipolar nuclear world, Mutual Assured Destruction (MAD) would prevent rising powers from engaging in conventional military competition with the unipole. There is historical evidence for this. When World War II ended, by virtue of its overwhelming military and economic supremacy, the United States incontestably was the most powerful actor in the international system. Indeed, 1945 was the United States’ first unipolar moment. As Robert Gilpin observed, “In terms of absolute power, the United States, in 1945, greatly surpassed the rest of the world. In addition to her vast industrial capacity, the U.S. virtually monopolized or controlled the three sources of power in the modern world: nuclear weapons, monetary reserves, and petroleum. She alone had the atomic bomb and the knowledge to produce what at the time was called the absolute weapon. American factories produced over 50 percent of the world’s output, and America held approximately 50 percent of the world’s monetary reserves.”[38] Nevertheless, notwithstanding the U.S. nuclear monopoly, American economic supremacy, and the fact that only the United States possessed long range power projection capabilities (both air and naval), between 1945 and 1949 (when it tested its first atomic device), the Soviet Union competed hard to balance U.S. power.[39] Moreover, even when the Soviet Union attained nuclear parity with the U.S. – and the Soviet-American nuclear relationship became one of MAD – both superpowers engaged in an intense conventional (as well as nuclear) weapons competition. Even after the Cold War’s end, it is clear that neither the U.S. nor Russia was willing to rely solely on nuclear weapons to ensure its survival or its interests. Thus, following the Cold War, Russia opposed NATO expansion, which as John Mearsheimer observes, “shows that it fears the idea of NATO’s conventional forces moving closer to its border. Russia obviously does not accept the argument that its powerful nuclear retaliatory force provides it with absolute security.”[40] Recently, Russia’s opposition to Ukrainian membership in NATO – which spurred its annexation of the Crimea and its support for separatists in eastern Ukraine – similarly demonstrates that Moscow remains deeply concerned about the possible further eastward extension of U.S./NATO military power.

There is also plenty of evidence that nuclear weapons do not deter conventional war either between nuclear armed states, or between a non-nuclear state and a nuclear state. Or to put it another way, far from being secure, even nuclear armed powers must worry about being involved in conventional wars. In 1999, for example, India and Pakistan – both of which were armed with nuclear weapons – fought the Kargil war.[41] Tensions between India and Pakistan remain severe enough that many international security experts worry that nuclear war could break-out at some point on the sub-continent.[42] In 1969, the Soviet Union and China – both nuclear powers – engaged in serious fighting along their Ussuri-River border. Perhaps even more telling than these examples, non-nuclear states have engaged in conventional wars with nuclear states. In 1950, notwithstanding overwhelming U.S. nuclear superiority, a non-nuclear China intervened against American forces in Korea. In 1973, non-nuclear Egypt and Syria launched a conventional war against nuclear-armed Israel. These examples support the insights of the stability/instability paradox: precisely because nuclear weapons are so terrifying, nuclear armed states could reasonably conclude that – as long as they limit their war aims – they could fight a conventional war against a nuclear armed rival without fear that a conflict would escalate to the use of nuclear weapons.[43]

In constructing his theory of unipolar durability, Monteiro rests the weight of his argument on the nuclear revolution. However, the nuclear revolution fails to buttress his argument, because there is too much evidence that the nuclear revolution does not affect states’ strategies in the manner Monteiro believes it does. That is, states do not act as if nuclear weapons guarantee survival, or render impossible conventional war – or even limited nuclear war. Therefore, contrary to Monteiro’s argument, regardless of the whether the unipole pursues a strategy of offensive, or defensive, dominance, rising powers can never feel secure when the distribution of power in the international system is so heavily titled in one state’s favor.

Clearly, states have not acted as if nuclear weapons are a sure guarantee of security. This means that even a unipole’s strategy of defensive accommodation does not alter the fact that in a unipolar world the prevailing imbalance of power is a potential threat to the security the other major powers. The nuclear revolution does not erase others’ uncertainty about the unipole’s intentions, it does not negate others’ concerns for their security; and it does not remove the motivation of rising powers to seek peer competitor status with the unipole. Ironically, Monteiro implicitly seems to understand this. He argues that if the unipole pursues an offensive dominance strategy – by trying to strangle the economic growth of a rising powers – “those powers in a unipolar world may continue to convert their growing latent power into military power beyond the point at which their survival is guaranteed by a nuclear deterrent…” (4-5). This, however, contradicts his claims about the impact of the nuclear revolution. It is therefore important to unpack his argument.

Monteiro argues that survivable second-strike retaliatory forces ensure survival (the “foremost” goal of states according to him) (32). Moreover he argues that in a nuclear world, conventional challenges to the unipole are irrational because of the risk of escalation. According to this logic, in a unipolar world it is irrational for any rising power to engage in a conventional challenge to the unipole’s privileged position in the international system. It is worth quoting the author at length:

In a nuclear world…no great-power war is winnable. As [Robert] Jervis has shown, survivable nuclear weapons make all-out war unwinnable. This means that major war in a nuclear world endangers a state’s existence, jeopardizing the initial premise of the argument that led to balancing in the first place – a preeminent interest in state survival.   Consequently, any threat of major war issued by a nuclear state itself threatens the survival of the state that issues it. In sum, the nuclear revolution renders absurd the ultima ratio of international politics – the ability to major wage major war rather than allow an adversary to threaten a state’s existence (92).

The nuclear revolution, Monteiro observes, “makes it hard to guarantee that any war between great powers will not escalate into a nuclear war” (92-93). In a nuclear world, conventional wars involving nuclear armed powers will not occur because of the risk of escalation. Similarly, limited nuclear wars will not be fought, both because of escalation risks, and because accepting defeat would imperil the loser’s survival.

The foregoing notwithstanding, Monteiro argues that a major power that gets in the cross-hairs of the unipole’s offensive dominance strategy, “has incentives to invest in additional military capabilities and put up a military challenge to the unipole” (80). Moreover, he suggests, that when a major power is the target of an economic constriction strategy – a strategy that threatens its long term survival – “war might prove a rational option, even between nuclear powers. (Whether it does depends on the loss in economic growth resulting from economic containment by an adversary relative to the likely cost of nuclear war, which need not be unlimited)” (51). [emphasis added] There are several problems with Monteiro’s claim that a unipole’s offensive dominance would prompt such a response. First – and glaringly – it collides head-on with his arguments about the nuclear revolution’s effect on international politics. Between nuclear armed states, the risk is omnipresent that any conflict could escalate to a catastrophic nuclear war. That is precisely why, according to Monteiro, major powers will avoid challenging the unipole’s power preponderance. If one truly buys into the logic of the nuclear revolution, it should make no difference whether the unipole pursues an offensive dominance or a defensive strategy: regardless of the unipole’s strategy, if a nuclear war occurs, the participating states will suffer horrifically. To put it slightly differently: if the specter of nuclear war deters when the unipole follows a defensive dominance strategy, it should equally deter even if the unipole follows an offensive dominance strategy. In either scenario, nuclear weapons are fearsome, and if nuclear war occurs the states involved will be equally dead.

If a major power targeted by the unipole’s offensive dominance/economic constriction strategy pushes back militarily, the pathways to a possible – even likely – conflict are obvious.   Because challenging the unipole militarily would threaten its power preponderance, the unipole would have strong incentives to engage in preventive war to maintain its dominant position in the international system. Moreover, if a major power instigates a security competition with the unipole, it is impossible to foresee where it will end. Either the nuclear revolution works, or it does not. Rather than being a function of the unipole’s strategy, the answer should hinge on the nuclear revolution’s logic. Monteiro can’t have it both ways. If the nuclear revolution prevents big wars when the unipole adopts a defensive dominance strategy, war equally must be ruled out even if the unipole follows an offensive dominance strategy.

Finally, there is an additional reason why it would be irrational for a major power to respond to a unipole’s offensive dominance strategy by challenging it militarily. In an economically interdependent world, it is improbable that even a unipole could credibly threaten the survival of a major power through a policy of economic containment. Moreover, such a strategy would almost certainly require a long time to work, and many things could derail that policy long before it accomplished its intended purpose.[44] Rather than risking even a conventional war with the unipole (which could escalate), a major power that was the object of the unipole’s economic containment policy would be better off to play for time. For a major power, the danger to state survival posed by the unipole’s offensive dominance strategy is remote in time, and uncertain in effect. On the other hand, in a nuclear world – if one accepts the logic of the nuclear revolution – military confrontation carries the risk of swift and terrible damage. A major power targeted by the unipole’s offensive dominance strategy truly would be ‘committing suicide for fear of death,’ to quote German Chancellor Otto von Bismarck if it responded by challenging the unipole’s power preponderance.

While his views about the effect of the nuclear revolution are shaky, on the issue of whether unipolarity is peaceful, Monteiro’s book is on solid ground. As he points out, by definition – given that the unipole is the only great power in the system – in a unipolar world, great-power wars cannot occur. But, as he points out, other kinds of interstate wars could occur – for example wars between regional powers, or minor powers, to use Monteiro’s term. “Unipolarity,” Monteiro argues, “will be prone to produce asymmetric and peripheral conflicts” (3). But it is the unipole itself that is most likely to be affected by the lack of peacefulness in a unipolar world. Monteiro offers a detailed theoretical framework for understanding why there is a high chance the unipole itself will be involved in fighting wars against what he calls “recalcitrant minor powers” (Iraq, North Korea, Iran, etc.) (152). Because these states lack the conventional military capability to defeat or deter the unipole, they will be tempted to acquire nuclear weapons in order to deter the unipole from attacking them, and the unipole will have corresponding incentives to fight preventive wars to ensure proliferation does not occur.

At the same time, although Monteiro provides an impressive theoretical gloss to the argument that unipolarity is not peaceful, there are other equally important explanations for this phenomenon that he does not consider. For one thing, there is what can be called the ‘unipole’s temptation,’ which is caused by the imbalance of power in its favor. Conscious both of its overwhelming military superiority, and of the fact that there are no other great powers capable of restraining its ambitions, a unipole is easily lured into overseas military adventures.[45] When it comes to hard power, a unipole has it, and seldom can resist flaunting it – especially when the costs and risk of doing so appear to be low. Thus, we should expect a unipole to initiate many wars, and to use its military power promiscuously. From this perspective, it is not surprising that since the Cold War’s end the United States has – in addition to Afghanistan and Iraq -intervened in such peripheral places as Panama, Somalia, Haiti, Bosnia, and Kosovo while simultaneously extending its military reach into Central Asia, the Caucasus region, and East Central Europe (except for Panama, none of these areas had ever been regarded as a place where the U.S. had vital interest).

Beyond the temptations generated by the possession of overwhelming power, there are two other – related – reasons why a unipole will need to fight wars. First, the very nature of a unipole’s power preponderance predisposes it to fight wars in order to maintain its leading position in the international system. As Robert Gilpin has observed, the dominant power earns its prestige – others’ perceptions of the efficacy of its hard power capabilities – by using military power successfully to impose its will on others.[46] When a unipole wields its military power conspicuously, others are put on notice that the prudent course of action is to accommodate its dominance rather than challenging it. In effect, a preponderant power believes that the frequent use of use of force has potent deterrent, or dissuasive, effects on other states.

Second, a unipole will want to maintain the prevailing international security and economic orders from which it benefits. Doing so means avoiding potentially destabilizing events – such as attempts by major powers to become military peer competitors – and also preventing major powers that lack nuclear weapons (Germany or Japan, for example) from getting them. To accomplish these objectives, the unipole must act as a security provider for other states to persuade them that they do not need to build up their own conventional or nuclear capabilities in order to be secure. In other words, the unipole must be prepared to provide extended deterrence. But extending deterrence is hard because those who shelter beneath the unipole’s security umbrella may question whether it would actually carry out its threats in a crisis. For extended deterrence to work, the unipole’s threats must be regarded as credible – both by potential adversaries and by its security dependents. Fighting wars against small powers in the periphery is an important mechanism for bolstering the unipole’s reputation for credibility. U.S. strategists hold the perverse belief that the best way to bolster credibility is by fighting wars – and showing that the United States will pay a blood price to defend its interests -in places that have little strategic or economic value to the United States. As Thomas Schelling’s famously observed, “Few parts of the world are intrinsically worth the risk of serious war by themselves…but defending them or running risks to protect them may preserve one’s commitments to action in other parts of the world at later times.”[47] The perverse logic that underlies the unipole’s strategy is that it is important to fight wars in places that do not matter, because – purportedly – that is how the unipole establishes it credibility and resolve.

To burnish its reputation for credibility, and its prestige, the unipole will beat up on small states. But in so doing, it is also is sending a clear Dirty Harry-like (the tough San Francisco detective memorably portrayed by Clint Eastwood) message to any major power that might be thinking of mounting a challenge by ascending to peer competitor status: ‘go ahead, make my day.’ In other words, if you try doing it, you will be sorry. Thus, then-Secretary of Defense Donald Rumsfeld – after extolling the displays of America’s military virtuosity in Afghanistan and Iraq – declared that those wars should be a warning to other states that might defy the United States: “If you put yourself in the shoes of a country that might decide they’d like to make mischief, they have a very recent, vivid example of the fact that the United States has the ability to deal with this.”[48] As Robert Gilpin pointed out, for a dominant power worried about a challenge to its position (actual or potential) from a rising power, the grand strategic playbook calls for preventive war: do it to them before they do it to you. Or, as (in the TV series The Sopranos) Mafia boss Tony Soprano was told by his chief henchman, Paul Walnuts, with respect to the head of a rival family, “clipping the guy is always an option.” Even in a nuclear world, a unipole can never be certain that it will not be challenged by a rising major power. By the same token, regardless of its actual intentions, a rising major power cannot be certain that the unipole will not view it as a threat and act accordingly. Because nuclear weapons are not, in fact, a sure guarantee of security, the traditional hallmarks of great power politics – balancing, the security dilemma – will be just as prevalent in a unipolar world as they are in bipolar and multipolar worlds.

An obvious question to be asked of a book laying out a theory of unipolarity is whether the present-day international system, in fact, is unipolar. For Monteiro, great power status is a function of military capabilities. He states that the possession of military power “on a par with the most powerful state(s) in the system” is the sine qua non of great power status (43). He then adds, “A state whose military power is grossly outmatched by others should not be called a great power” (43). So far so good. Few students of great power politics would disagree. But then, Monteiro takes a big leap beyond the traditional – what he calls “defensive” – definition of great power status (the ability to prevail in a one-on-one showdown with another great power) (43).[49] Instead, he introduces a new definition of great power status: “great powers must fulfill a military power-projection requirement. Specifically, a great power must possess the ability to engage unaided in sustained politico-military operations in at least one other relevant region of the globe beyond its own on a level similar to the most powerful state in the system” (44).

Monteiro accurately states that currently the U.S. is the only state that actually can project power into regions other than its own and carry out sustained operations in distant corners of the globe (44). As he notes, “no other state comes close” to the United States in this respect (44). He discards the defensive (traditional) definition of great-power status because, “it is unable to capture the ways in which the United States unparalleled power projection capabilities affect the workings of international politics” (44). But making great-power status contingent on overseas power projection capabilities is also very convenient for his theory of unipolar politics – indeed it is a theory-saver – because this definition has the effect of excluding China as a peer competitor of the United States. Monteiro’s definition, however, is a-historical. For example, in the eighteenth and nineteenth centuries, Prussia and Hapsburg Austria lacked overseas power projection capabilities. Yet they were acknowledged as great powers. Should we now re-write diplomatic history to downgrade them from great power status because they do not fit Monteiro’s definition? How should we conceive of the period between 1945 and the mid-1960s? The received wisdom, of course, is that bipolarity prevailed in that period. Yet, during the two decades following World War II’s end, the Soviet Union lacked overseas power projection capabilities, which it only began to acquire after the 1962 Cuban Missile Crisis.[50] This raises the question of whether the world was truly bipolar from 1949 until the mid-to-late 1960s (when the Soviet navy’s blue-water presence first became noticeable). If Monteiro applies his definition of great power status even-handedly, the answer would have to be “no.”

The issue of how to define great power status cuts to the chase: is today’s world still unipolar? Concretely, the question that must be asked is what impact the rise of China – the 800 pound gorilla in the room in Theory of Unipolar Politics – is having on the U.S. role as the international system’s unipole. Monteiro’s answer is ‘not much.’ He shrugs off the implications of China’s rise. For him, the world is – and will remain for a long time – unipolar because “the global distribution of military power continues to place the United States in a league of its own” (117). Monteiro is not much troubled by the implications of China’s economic rise, which, he writes does not in and of itself foreordain the end of U.S. military power preponderance, which is the defining feature of unipolarity” (117). Although he concedes that China will eventually overtake the U.S. economically, he believes this is a long way off (the late 2030’s). Moreover, he argues, even if China overtakes the U.S. in aggregate GDP, its per capita GDP, will be well below that of the United States. Monteiro believes that per capita GDP is the key metric that determines a state’s ability to develop technologically advanced weapons systems, and that therefore China will have difficulty challenging U.S. military preponderance.[51] To date, according to Monteiro, China has not engaged in military balancing against the U.S. (114). More to the point, he asserts that even when it reaches the point that its economic power would support a militarily challenge to the United States, China will not do so because the U.S. has accommodated China’s rise, and also acts as a status quo power in China’s region, East Asia.

A cornerstone of Monteiro’s theory of unipolarity is his claim, that – in a nuclear world – military preponderance is “in principle independent from the distribution of economic power” (25). This explains why, according to him, the unipole should follow a policy of defensive dominance, and acquiesce in the economic rise of major powers. According to Monteiro, the unipole can retain its military dominance (which, as he mentioned above, for him is the sine qua non of unipolarity), even if it is overtaken economically by one (or more) of the rising powers (208).

In the unipolar world that he imagines, the economic rise of major powers poses no threat to the unipole’s preponderance. As long as the unipole accommodates their economic growth, he argues, rising powers have no reason to challenge the unipole’s dominance by converting their economic power into military power. This contention that economic and military power is divisible rests, however, on some pretty heroic assumptions. It is an argument that brushes aside most of what we know – theoretically and empirically – about the rise of great powers.

In October 2014 the International Monetary Fund announced that China had overtaken the United States as the world’s largest economy (measured by purchasing power parity).[52] That China has displaced the U.S. as the world’s largest economy is significant geopolitically, as well as economically. The pattern of great power rise is well established. First, as rising great powers become wealthier, their political ambitions increase and they convert their newfound economic muscle into military clout.[53] Already, China is engaged in an impressive military buildup. While China has not yet caught up to the United States’ sophisticated military technology, it clearly is narrowing the U.S. advantage. Second, rising powers invariably seek to dominate the regions in which they are situated.[54] According to Monteiro, however, the fact that China is acquiring military capabilities to support a bid for regional hegemony in East Asia should not be a matter of concern, because “unipolarity is not challenged by a rising power boosting its military capabilities within a regional framework” (107). This is an Ivory Tower perspective on the implications of China’s rise – not one that reflects the real world concerns of U.S. policymakers.[55] Rising powers must secure dominance in their own regions before they begin to project power to distant regions. Third, as they rise, new great powers acquire economic and political interests abroad, and once having achieved dominance in their home region, they seek to acquire the power projection capabilities to defend those interests.[56]

In the 1990s, China was a great power in waiting. Because there were no other great powers with whom it could coalesce against the United States, a strategy of internal balancing and great power emergence was China’s only option for countering American dominance.[57] The late 1970s economic reforms of China’s “paramount leader” Deng Ziaoping launched China on its trajectory to become – or, more correctly, re-emerge – as a great power. As Avery Goldstein observes, the aim of Deng’s reforms was to kick-start China’s “rise to the status of a true great power that can shape, rather than simply respond to, the international system in which it operates. China’s pursuit of this goal would be part of, and contribute to, a long-term global trend transforming the currently unipolar system in which the United States is the sole remaining superpower into a multipolar system in which China would become one of several great powers.”[58] For some three decades (beginning with Deng Xiaoping’s economic reforms) China kept a low profile in international politics, and avoided confrontation both with the U.S. and its regional neighbors. To spur its economic growth and modernization, China integrated itself in the American-led world order. China’s self-described “peaceful rise” followed the script written by Deng Xiaoping: “Lie low. Hide your capabilities. Bide your time.”[59] When the power differential between the U.S. and China was huge – as it was in the fifteen years following the Cold War’s end – China embraced “the logic of bandwagoning” with the United States and signed-up for membership in the American-led international economic system so that it could reap the gains of economic growth.[60] This did not mean China’s long-term intentions were benign, however. Beijing’s longterm goal was not simply to get rich but rather to become wealthy enough to acquire the military capabilities it needs to compete with the U.S. for regional hegemony in East Asia.[61]

This is what China now is doing, and it is why it is on a geopolitical collision-course with the United States. The dynamics of the Sino-American competition illustrate the problems with Monteiro’s definition of great power status. By making overseas power projection capabilities the prerequisite for great power status, he misses the most crucial trend shaping contemporary international politics: China’s rise, and its bid for dominance in East Asia. Against Monteiro’s outlier, theory-saving definition of great power status – is the test of a ‘rose by any other name’ (or, ‘if it walks like a duck…’). China’s strategic behavior conforms to the historical pattern of great-power emergence. In East Asia today we see two of the most important hallmarks of great power competition: a struggle for regional supremacy, and an ongoing power transition. Monteiro’s definition of great power status may result in China’s exclusion from the great power ranks. However, the facts on the ground in East Asia sure suggest that the U.S. and China are engaged in a traditional great-power rivalry. When it comes to defining what is a great power, we might do better to focus less on China’s overseas power projection capabilities, and focus more on its growing acquisition of weapons systems that fairly soon will enable it to either evict the U.S. outright from East Asia, or make the risks of staying so high that the United States will decide to pull back.

China’s great power emergence raises obvious questions about U.S. grand strategy. Monteiro offers some thoughts about the unipole’s (or U.S.) grand strategic alternative. These are, he says, offensive dominance, defensive dominance, and disengagement. All three strategies involve what he calls conflict costs. As we already have seen, a defensive dominance strategy means the United States will find itself fighting wars against recalcitrant minor powers (to keep them in line and prevent them from acquiring nuclear weapons). Additionally, although not discussed by Monteiro, the ‘unipole’s temptation,’ and the need to bolster the U.S. reputation for credibility and resolve will embroil the United States in wars of this type. However, as Monteiro sees it, although a defensive dominance strategy has conflict costs for the U.S., there are no competition costs. That is, as long as the United States allows the rising major powers to grow economically, they will not seek to build up their conventional capabilities and challenge the U.S. militarily.

An offensive dominance strategy involves both conflict costs and competition costs for the unipole. In terms of wars with recalcitrant minor powers, the offensive dominance strategy would have the same consequences for the unipole as the defensive variant. Moreover, because an offensive dominance strategy means that the unipole will try to stifle the growth of rising powers, or project power into their home regions, there is a significant risk that one (or more) of them may push back by mounting a military challenge to the unipole. Hence, there is a potentially significant competition cost to the unipole in pursuing this strategy. By prompting rising powers to build-up militarily, the perverse consequence of a unipole’s offensive dominance strategy would be to stimulate (even in a nuclear world, he says) attempts by one (or more) of them to restore a balance of power in the international system. In other words, by following an offensive dominance strategy the unipole would be following a strategy likely to undermine unipolarity’s durability. Hence, Monteiro believes this would be a suboptimal strategy for the U.S.

Monteiro’s take on the grand strategic options of the unipole (or U.S.) has both theoretical and empirical problems. First, his prescription for U.S. China policy misses a big point. Using his analytical framework, current U.S. policy is a mix of both offensive and defensive dominance (or as policy analysts would say, it combines ‘containment’ with ‘engagement’). In other words, it combines the worst of two grand strategic worlds. To be sure, far from limiting China’s economic growth the U.S. has facilitated it. However, far from staying out of China’s region the United States is up to its neck geopolitically in East Asia. The Obama administration’s Asian ‘pivot’ (or re-balance) reflects U.S. determination to maintain its preponderance in East Asia, and to prevent China from becoming the regional hegemon there. Second, his argument that offensive and defensive dominance have different consequences for the unipole hinges on whether his claims about the effects of the nuclear revolution are correct. The nuclear revolution is the weak link in Monteiro’s argument. As discussed above, there is no reason to believe nuclear weapons actually abolish balancing behavior, or rule out of court the likelihood that rising powers will attempt to restore a systemic balance of power. In other words, even in a nuclear world new great powers will rise and bring about the end of the unipolar distribution of power. In this respect, it does not matter if the unipole follows an offensive dominance, or a defensive dominance, strategy. Either way, there will be competition costs.

The key grand strategic question is whether the United States should continue to follow a strategy that aims at preserving a unipolar distribution of power, or, instead, follow a more modest strategy (including offshore balancing and restraint).[62] As the author notes, a less engaged grand strategy would ensure a peaceful life for the unipole. The downside, however, is that the level of conflict in the international system would rise, as would the pressures for proliferation. The unipole’s disengagement, Monteiro argues, would “make room for competition among major powers, ultimately leading them to augment their conventional capabilities and put an end to U.S. power preponderance regardless of which economic strategy Washington implements. Consequently, disengagement fails to guarantee the continuation of the unipole’s power preponderance” (215). [emphasis in original]

Monteiro believes that the benefits that accrue to the U.S. from its power preponderance outweigh the conflict costs that the U.S. must pay to preserve unipolarity. In particular, he believes U.S. military preponderance is the bedrock for what he sees as the benefits to the United States from an open international economic system.[63] He argues that the United States can easily bear the economic costs of fighting frequent wars to preserve a unipolar system. Monteiro’s view that the U.S. should seek to perpetuate unipolarity certainly is defensible. It is also imminently contestable. This review is not the place to lay out comprehensively the case for the U.S. to adopt a less engaged grand-strategy – such as offshore balancing or restraint. For now, it can simply be observed that the economic cost of being a unipole are becoming increasing more difficult for the U.S. to sustain, and will become more so in the next decade or two.[64] It is also far from evident that the cost/benefit ratio of a grand strategy upholding economic openness still cuts in favor of the U.S. As Monteiro himself says, the U.S. has been almost continually at war for nearly a quarter of a century (and has been on a war-footing since the Cold War’s early days). Beyond the economic costs of this policy, there also have been considerable intangible costs (which Monteiro neither acknowledges nor discusses). There is a strong argument that, regardless of the systemic effects, the United States itself would benefit greatly by shifting the risks and costs of security to the states that now shelter under the U.S. umbrella. Monteiro is almost certainly correct in suggesting that the next big U.S. grand strategic debate will between those who believe the U.S. benefits from unipolarity, and those who believe otherwise. It is far from obvious, however, that the game of preserving the United States unipolar power preponderance is worth the candle.

Review by Jeffrey W. Taliaferro, Tufts University

The collapse of the Soviet Union in 1991 left the United States as the unipole—the only great power in the international system. For the past twenty-five years, international- relations theorists have debated whether unipolarity is durable or just an aberration that will eventually give way to a renewed systemic balance-of-power. They have also debated what type of grand strategies that United States ought (or ought not) pursue and the likely implications of particular U.S. military postures for regional peace and the long-term health of the American economy. Yet many of the debates about the durability of unipolarity and U.S. grand strategy are still informed by theories developed during the Cold War, that is, by theories developed to explain international politics in a bipolar system. What has been lacking is a systemic theory to explain how unipolarity influences both the strategic behavior of the unipole and the strategic behavior of other categories of states in the system.

Nuno Monteiro’s Theory of Unipolar Politics seeks to fill this gap in the international- relations literature. It fills that gap admirably. Monteiro poses three ‘big’ questions about how a unipolar system works: Is it durable? Is it peaceful? And, what is the optimal grand strategy for the unipole (the United States)?

The durability of unipolarity depends upon two variables, one systemic and the other strategic. The systemic variable is the expected cost of war between a rising challenger and the unipole. The higher the expected cost (determined by the technology of warfare) then the narrower the range of situations that might temp a rising military challenger. In a nuclear-armed world, the expected costs of war between the unipole and potential challenger are extraordinarily high.

The strategic variable pertains to the unipole’s strategies regarding the economic growth of major powers (the second-tier states). If the unipole accommodates the economic growth of rising major powers, then those states have no incentive to invest in greater military capabilities. Conversely, if the unipole attempts to contain their economic growth, then major powers have a greater incentive to invest in additional military capabilities (especially power-projection capabilities) beyond those needed to assure their immediate security and survival.

A unipolar international system is not necessarily a peaceful one. Although nuclear weapons make the expected costs of war between the unipole and one or more major powers prohibitively high, unipolarity generates conditions for significant interstate conflict. As Monteiro writes, “Unipolarity will generate abundant opportunities for war between the unipole and recalcitrant minor powers that do not have the capabilities or allies necessary to deter it. It will also make ample room for conflict among minor powers, which are less likely to be disciplined by great power allies, as would be the case when an overall balance-of-power is present. As a result, unipolarity will be prone to produce asymmetric and peripheral conflicts” (5).

Finally, Monteiro admits, “Because the optimal strategy for a unipole varies depending on specific features of its situation—namely the costs of war and the benefits its extracts from its power preponderance—that strategy cannot be determined a priori theoretically”(5). Nonetheless, Monteiro contends the United States’ long-term interests are best served by pursuing a grand strategy of defensive accommodation, which entails a military strategy aimed at preserving the territorial status quo in various regions (defensive dominance) in conjunction with an economic strategy that accommodates the interests of rising major powers (accommodation).

Theory of Unipolar Politics is a superb book. Monteiro integrates the hitherto disparate literatures on polarity, nuclear deterrence, nuclear proliferation, and conventional military power into a cohesive deductive framework. His theory purports to explain the paradox of why unipolarity can generate significant conflict between the unipole and one or more minor powers, while simultaneously mitigating the likelihood of significant conflict between the unipole and the major powers.

Monteiro challenges what has become the “conventional wisdom” among some international-relations scholars that a unipolar world will be largely peaceful due to a myriad of factors, including overwhelming U.S. power preponderance, nuclear weapons, economic interdependence, and the fact that many of the second-tier states are liberal democracies and/or longstanding U.S. allies. That fact that the United States has been at war for fourteen out of the twenty-four years between 1990 and 2014 and has embarked on an open-ended air war against the so-called Islamic State would seem to bely the conventional wisdom about the peacefulness of unipolarity.[65]

The choice of title, Theory of Unipolar Politics, pays homage to Kenneth N. Waltz’s seminal Theory of International Politics.[66] Like Waltz, Monteiro presents an elegant systemic theory that purports to explain a small number of big and important things about international politics. Furthermore, like Waltz, Monteiro is actually quite modest about the empirical scope of his theory. As he writes, “a theory of unipolarity, although necessarily broad, provides an account of how the absence of a systemic balance-of-power affects each of the key phenomena in international politics, such as peace, balancing, and U.S. strategy…At the same time, unipolarity is not the whole story. A unipolar structure of international politics is not sufficient for many of the processes and outcomes we have witnesses since the end of the Cold War” (59). Finally, like Theory of International Politics thirty-six years ago, the present author’s book will likely be influential because it is provocative.

There are two important areas, however, where Monteiro parts company with Waltz and to some extent with other structural realists as well. First, he abandons Waltz’s strict dichotomy between theories of international politics and theories of foreign policy. Consequently, he does not find himself in the untenable position of claiming his empirical theory merely explains patterns of international outcome, on the one hand, and making normative pronouncements on United States foreign policy, on the other hand.[67] This enables Monteiro to offer a clear, but sobering set of recommendations for Washington policymakers: If the United States wants to remain the unipole, then it ought to pursue an overall grand strategy of defensive accommodation, but with the understanding that such a strategy will entail frequent U.S. military interventions against recalcitrant minor powers in various regions.

Second, and perhaps more significantly, Monteiro shifts the debate about the contemporary relevance of balancing theories. For twenty-five years, proponents of balance-of-power realism have looked for evidence of balancing against the United States in all the wrong places: namely, among major powers such as Russia, China, France, and India.[68] Since Waltz’s balance-of-power theory holds that any anarchic international system will return to equilibrium and given the apparent paucity of “hard” balancing by major powers against the United States, other scholars developed the concept of “soft” balancing, the use of diplomatic, economic, and other means well short of full-fledged arms racing and alliance formation, to impose constraints on Washington without unnecessarily provoking the unipole’s retribution. The entire soft-balancing debate was largely in reaction to the aggressive unilateralism of the George W. Bush administration after the 9/11 terrorist attacks, in particular the 2001 Bush Doctrine and the ensuing Iraq war.[69]

Instead, Monteiro’s theory of unipolar politics provides a good ‘first cut’ explanation for the dynamics we have actually witnessed since 1990, namely actively balancing against the United States, not by major powers, but rather by recalcitrant (and vulnerable) states such as Iraq, North Korea, and Iran. Theories of balancing (but not theories of systemic balances-of-power) are indeed relevant to unipolar systems, however it is not the major powers that have a structural incentive to balance against the unipole, but rather the minor powers.[70] Furthermore, by making survival the primary motive of all states and by incorporating the role of nuclear weapons (the ultimate guarantor of any state’s survival) and the importance that major powers attach to their own economic growth, Monteiro shows that there strong economic disincentives for major powers to balance against the unipole. It is not simply that the costs and risks of counterbalancing an existing unipole are too high for major powers, as Stephen Brooks and William Wohlforth claim, but also that most of those major powers will have an interest in preserving the status quo, as long as the unipole does not try to thwart their economic growth.[71]

Theory of Unipolar Politics is an impressive achievement. However, there are a few weaknesses in Monteiro’s theory and the empirical evidence he marshals in support of it.

Monteiro’s focus on the grand strategic options of the unipole is well placed, as is his focus on the combinations of military postures the unipole adopts in various regions and economic strategies the unipole pursues vis-à-vis rising major powers. I recognize that three possible military postures available to the unipole—offensive dominance, defensive dominance, and disengagement—represent ‘ideal types’ necessary for the purpose of theory building. Nonetheless, there seems to be an inconsistency between Monteiro’s treatment of offensive dominance and defensive dominance, both of which the United States could pursue in specific regions, and a strategy of disengagement. Disengagement would require the U.S. simultaneously to maintain military preponderance and abstain from any interference in regional balance-of-power outside the Western Hemisphere.

Monteiro identifies two conditions for a disengagement strategy: it must be global and it must be complete. From a purely theoretical perspective, it seems reasonable that the unipole’s disengagement would have to be global and complete in order for minor powers to escape the need for extreme help. However, the likelihood that any presidential administration in Washington would contemplate, let alone attempt to pursue, such a drastic retrenchment is exceedingly low. The sunk costs of maintaining America’s preponderant position in the international system are enormous. Barring a catastrophic economic collapse, I am hard pressed to think of any scenario that might cause the United States to terminate all standing alliances, revoke all security guarantees, and abandon its network of forward military bases.[72]

Another weakness in Monteiro’s theory is the absence of a causal mechanism for grand strategic adjustment by the unipole. The conditions under which the unipole might switch from a grand strategy of defensive accommodation (defensive dominance and economic accommodation of rising major powers) to a grand strategy of offensive accommodation (offensive dominance in one region and economic accommodation of rising major powers) are unexplained. Why, for example, did the United States switch from strategy of offensive dominance in Europe (1991-2000) to one of defensive dominance (2000-present)?

I agree with Monteiro that the George H.W. Bush and Bill Clinton administrations sought to solidify the United States’ dominant military role in Europe after the Cold War by preserving NATO, expanding NATO eastward to include former Warsaw Pact members and even the Baltic Republics, and going to war with Serbia over the fate of Kosovo in 1999. But why did the U.S. then switch to a defensive dominance strategy after 2000? After defeating Serbia, were there simply no more recalcitrant minor powers in Europe? Is the presence of a recalcitrant minor power in a region a necessary and/or sufficient condition for the unipole to pursue a strategy of offensive dominance? In light of Russian President Vladimir Putin’s 2014 annexation of Crimea and his military support for pro-Russian separatists in eastern Ukraine, what grand strategy would Monteiro’s theory expect the U.S. to adopt vis-à-vis Russia, a recalcitrant (and nuclear armed) major power?

More importantly, why did the United States switch from strategy of defensive dominance in the Middle East (1989-2000) to a strategy of offensive dominance (2001-2009), when the ostensible threat posed by Iraq’s weapons of mass destruction (WMD) programs actually diminished after the 1991 Persian Gulf War and the subsequent six years of intrusive inspections by the United Nations Special Commission (UNSCOM)?

In order to explain why the George W. Bush administration not only embarked upon a strategy of offensive dominance in the greater Middle East after the 9/11 terrorist attacks, but targeted Iraq, which was clearly a recalcitrant minor power in deep relative decline, instead of Iran, a recalcitrant minor power in relative ascendancy, one needs to incorporate unit-level variables into Monteiro’s theory. After all, Iran had an active nuclear weapons program and the U.S. intelligence community was aware of its existence in the late 1990s. Given Tehran’s nuclear aspirations, avowed hostility toward U.S. regional allies Israel and Saudi Arabia, and military support for Hezbollah in Lebanon, Iran ought have been seen by Washington as the greater threat than Iraq after 2001.Yet, intelligence analysts and policy makers in the second Bush administration consistently overestimated Iraq’s (largely defunct) Weapons of Mass Destruction (WMD) programs after the withdrawal of UNSCOM in late 1998.[73]

This raises a related question about the demarcation that Monteiro draws between the major powers and the minor powers. The possession of nuclear weapons seems to be the only criterion that separates the major powers from the minor powers in a unipolar system. I agree with Monteiro and nuclear deterrence theorists that possession of even a rudimentary nuclear arsenal guarantees a state’s survival. I also acknowledge that none of the major powers that Monteiro identifies—Russia, China, the United Kingdom, France, India, Israel, Pakistan, and North Korea—are capable of projecting military power far beyond their immediate vicinity. However, I question whether non-nuclear armed states that nonetheless have large economies and sizable conventional military capabilities and that play pivotal roles in their respective regions, such as Germany and Japan, ought to be excluded from the ranks of the major powers.

Why is a state like North Korea grouped among the major powers? While North Korea does have rudimentary nuclear arsenal, a sizable number of intermediate and medium range ballistic missiles, and the capability to launch cyber-attacks on other states and private sector actors (as illustrated by the November 2014 infiltration of Sony Corporation’s networks), its economy is in shambles. Possession of nuclear weapons and ballistic missiles does make the costs and risks of attacking North Korea prohibitive for the United States. But then Iran, which has not yet achieved nuclear breakout, is arguably better positioned to project its influence in the Persian Gulf/Middle East than a nuclear-armed North Korea in East Asia.

The concept of a ‘recalcitrant’ minor power requires further explication. Monteiro writes about recalcitrant minor powers that seek to challenge the international status quo by either the revision of territorial boundaries in their region and/or the clandestine acquisition of nuclear weapons, both of which will bring them into conflict with the unipole. According to Monteiro’s theory, survival seems to be the primary motivation for such states.

The main distinction between a recalcitrant’ minor power and all other minor powers appears to be the former’s willingness to take great risks to ameliorate its predicament of extreme self-help. What then might explain the risk aversion of the “obedient” minor powers that, I presume, are also in a predicament of extreme self-help? In other words, why do we not see more instances of recalcitrant minor powers, if, by virtue of not having a nuclear deterrent, every minor power is in a predicament of extreme self-help?

Monteiro examines the conflict-generating dynamics resulting from the unipole’s pursuit of offensive-dominance using the cases of the U.S. wars in Kosovo (1999) and Iraq (2003-2011). However, as Monteiro observes, “U.S. forces have been employed in four interstate wars—Kuwait (1991), Kosovo (1999), Afghanistan (2001-), and Iraq (2003-2011)—in addition to many smaller interventions including Bosnia, Haiti, Somalia, and Sudan. As a result, the United States has been at war for fourteen of the twenty-four years since the end of the Cold War” (181).

Do failed or failing states fall into Monteiro’s archetype of a minor power? Likewise, do transnational terrorist networks that find safe-havens in failed states—such as al-Qaeda in Afghanistan from 1996 to 2001—or which seize and control territory from states—such as the so-called Islamic State which seized large swaths of territory in Syria and Iraq in summer 2014—constitute minor powers? These are not inconsequential questions, since the United States will likely engage in low-level military operations against non-state or quasi-state entities like al-Qaeda, al-Qaeda in the Arabia Peninsula (AQAP), and the Islamic State (also called ISIS or ISIL) for some time to come.

The above weaknesses and questions aside, Theory of International Politics, is outstanding book. Monteiro has made a major contribution to international relations theories and our understanding of the dynamics of international politics in a unipolar world.

Author’s Response by Nuno P. Monteiro, Yale University

When I started working on Theory of Unipolar Politics a decade ago, the scholarly debate on whether the post-Cold War, U.S.-led world order was durable had long been stuck. On one side, declinists had, since the fall of the Soviet Union, argued that the United States, like every hegemon in the past, was fated to decline. Opposing them, primacists argued that U.S. power preponderance was destined to last. Not much has changed in the intervening decade. Successive waves of declinist scholarship have reaffirmed the inevitability of U.S. decline, increasingly with a tone of impending doom. Each time, primacists have criticized these arguments, reiterating their view that U.S. preponderance is here to stay.

My first purpose in writing Theory of Unipolar Politics was to ‘unstick’ this debate. My intuition was, and remains, that each side in the declinism versus primacism debate was partially right. Certainly, each side has been able to harness some empirical data in support of its own position. Their arguments are, so far, empirically equivalent – because they are under-specified. While declinists point to the rapid economic rise of China, primacists focus on the continued military preponderance of the United States. In order to move forward, I thought, we needed an integrated theory of unipolarity. Specifically, we needed a theoretical framework that would help us make sense of what is the key novelty of the post-Cold War era: the significant difference between the economic and military balance of power. China has been rising far more rapidly in economic terms than in the military realm. To understand world politics in the last quarter century, I wagered, we need a theoretical framework capable of making sense of this disparity between the balances of economic and military power.

At the same time, existing scholarship had, in my view, failed to highlight the ways in which the absence of a counterbalancing power had contributed to frequent U.S. involvement in military conflicts. By the mid-2000s, as I was beginning to ponder the topic, it was becoming increasingly clear that in the post-Soviet era, the United States was relatively unconstrained in its use of force against any minor powers that refused to hop on the American bandwagon. Yet, I could find no scholarship theorizing the relationship between U.S. military power preponderance and a higher incidence of war involving the United States. Could it be a coincidence that all these wars – Kuwait, Kosovo, Afghanistan, Iraq – were taking place when U.S. power was finally unconstrained by a peer competitor? Hardly, I thought. Those experiencing the sharp end of American power seemed to agree. After a U.S.-led coalition routed Iraqi forces from Kuwait in 1991, Iraqi foreign minister Tariq Aziz lamented: “If we still had the Soviets as our patron, none of this would have happened.”[74]

My second aim in Theory of Unipolar Politics was therefore to reconcile IR theory with the war-proneness of the United States in the past quarter century. Clearly, existing scholarship was right in arguing that the absence of a peer competitor made great-power war unlikely, indeed impossible.[75] At the same time, U.S. military preponderance seemed to be contributing to a frequent use of force on the part of the United States. A theory of unipolarity had to account for both realities, even if this possibly meant that the net effect of the Soviet demise on world peace was unascertainable.

As I started digging, it gradually became clear that answering these two questions – whether unipolarity was durable and whether it was peaceful – required two theoretical moves. To begin with, we needed to complete (or at least continue) the work of reconciling balance-of-power theory with the nuclear revolution.[76] If nuclear weapons do indeed guarantee state survival, then in the nuclear age states can achieve the goal of balancing – ensuring survival – without matching the conventional capabilities of other states. This could allow for the maintenance of a systemic imbalance in conventional capabilities among nuclear states, a feature of the post-Cold War world, in which the United States has unparalleled conventional power-projection capabilities. At the same time, this ‘silver bullet’ character of nuclear weapons would prompt states that find themselves at odds with the United States – and now that the Soviets were gone, without a viable potential security sponsor – to attempt to pursue a nuclear arsenal, something Washington would likely oppose. Herein, I thought, lay at least part of the reason for the frequent involvement of U.S. forces in wars against minor powers. This became my third purpose in writing Theory of Unipolar Politics: to push for a better articulation between balance-of-power theory and the nuclear revolution, delineating the effects of nuclear weapons both on the possibility of an enduring systemic imbalance of conventional power and on the consequences of this new possibility for peace.

Furthermore, in a second theoretical move, I felt that we needed to bring contingency back into our views on unipolarity, particularly in what concerned the effects of different U.S. strategies. Clearly, a preponderant military power such as the United States has considerable leeway in determining its own strategy – a reality emphasized by the seemingly endless debate over what is the right grand strategy for the United States. Yet, existing theories about the post-Cold War world were largely deterministic. Either U.S. strategy played no role in the argument or it was important but a particular strategic choice – usually some form of liberal internationalism – was taken for granted. From my perspective, it made little sense that our predictions about the peacefulness and durability of the U.S.-led order did not incorporate the freedom of contemporary U.S. strategic choice. Reconciling structural theory with the ongoing debate on U.S. grand strategy by highlighting the consequences of U.S. strategic choices for the durability and peacefulness of the current international system became my fourth purpose for Theory of Unipolar Politics.

While working towards these goals, I realized that it was impossible to make much progress without running into definitional issues. From here emerged the fifth and final goal I had for the book: to introduce some definitional precision into debates on the future of world order and of the U.S. role in it. What is a great power? Is the world unipolar? If so, are there any meaningful differences among other states? What grand strategies can a great power implement? Decades into the ‘polarity, schmolarity’ debate, as critics might label it, there are enough answers to each of these questions that whether any argument is right or wrong depends at least in part on which definitions one picks. So I decided to start from scratch and define my key terms.

What emerged is a unified theory of unipolar politics. I started out by assuming that states act rationally and aim primarily at guaranteeing their survival and amassing wealth, which is necessary for the long-term viability of the state. From here, I separated states into three types: great powers, major powers, and minor powers. Great powers have the ability to defend themselves and possess unsurpassed power-projection capabilities; major powers have the former but lack the latter; minor powers enjoy neither. Our world is unipolar because one country, the United States, has unparalleled power projection capabilities.

Then, I laid out the simplest possible typology of grand strategies available to a great power in a world without peer competitors – i.e., a preponderant power, or unipole – separating the military and economic realms. Militarily, in each region of the globe, a unipole might attempt to revise the status quo further in its own favor, through what I label a strategy of offensive dominance; it might defend the existing status quo, implementing a strategy of defensive dominance; or it might decide to remain uninvolved, disengaging from the region. Economically, a unipole might attempt to contain or accommodate other states’ growth. I argue that a unipole will choose its strategy through a cost/benefit calculus that accounts for the level of conflict in which each option is likely to involve it (what I label the ‘conflict cost’ of the strategy), as well as the potential for great-power competition the strategy is likely to generate (what I label the ‘competition cost’ of the strategy). Conflict costs vary according to military technology. Competition costs vary depending on the benefits the unipole extracts from its power preponderance: the greater these benefits, the higher the cost of a strategy that is likely to generate competition, i.e., to lead major powers to balance against the unipole, ending its power preponderance.

Using these basic blocks, I explored the potential durability of a preponderance of conventional military power, as well as its effect on the overall peacefulness of the international system. In a world without nuclear weapons, survival is best guaranteed by matching the military capabilities of other states – through domestic mobilization and inter-state alliances – such that a preponderance of power is not durable. In a nuclear world, however, state survival is virtually ensured by the possession of a nuclear arsenal. A preponderance of conventional military power in one state does not per se threaten the survival of nuclear states. Therefore, a preponderance of conventional military power is potentially durable as long as the preponderant power accommodates the economic growth of rising major powers while upholding the status quo in their regions. If the unipole tries to contain the economic growth of rising major powers, attempts to revise the status quo in their regions in its own favor, or disengages from these regions, affected rising major powers will balance, eventually reestablishing a systemic balance of conventional power. Using these arguments, I account for why China, which by now has (relative to the United States and measured in terms of GDP) greater economic power than the Soviets had at any point during the Cold War, opted nonetheless to remain a regional military power with limited nuclear and conventional capabilities: the United States has accommodated China’s economic growth and upheld the status quo in East Asia.

At the same time, a preponderance of conventional military power makes room for significant conflict. If the preponderant power remains militarily engaged around the world, as the United States does, it will be involved in frequent wars against recalcitrant minor powers that attempt to revise the status quo in their favor either territorially or militarily, for example by investing in nuclear weapons. The preponderant power is likely to oppose these developments, if necessary by force. If the preponderant power, on the contrary, disengages militarily from a particular region, then states in this region will be unconstrained by systemic pressures and there is no reason to expect the region to be more peaceful than it would be if the world had two or more great powers. The unipole’s grand strategic choices, then, influence the type of conflict we will witness but not its level, since each strategy makes room for significant conflict, making it hard to argue that unipolarity has a pacifying effect vis-à-vis other configurations of the international system. I then use these arguments to account for why the last quarter century, which represents only around ten percent of U.S. history, represents more than thirty percent of the country’s total wartime.

***

The reviewers in this roundtable have generously scrutinized each component of Theory of Unipolar Politics. To have such excellent scholars as Michael Beckley, Christopher Layne, and Jeffrey Taliaferro conduct such a thorough examination of the book is particularly gratifying – as is having William Wohlforth, a towering figure in these debates, introduce this roundtable. Their criticisms give me ample opportunity to clarify the arguments I made, so this roundtable may help to move debates on contemporary world politics forward. Overall, the reviewers criticize three aspects of Theory of Unipolar Politics: my view that the world is unipolar, my argument that unipolarity is potentially durable, and my account of the sources of conflict in a unipolar system. I address these criticisms in turn.

I begin with Christopher Layne’s objections to my view that the current international system is unipolar. Layne argues that my definition of great power is wrong; that China is already a great power; and that, consequently, the world is not unipolar. In Theory of Unipolar Politics, I defined ‘great power’ as follows:

A great power is a state that, in addition to having robust capabilities in all the relevant elements of power, is not significantly surpassed in two aspects of military power. The first aspect is the great power’s capability to defend itself from aggression. … A great power must have a plausible chance of avoiding defeat in an all-out defensive war against the most powerful state in the system. …

In addition, great powers must fulfill a military power-projection requirement. Specifically, a great power must possess the ability to engage in sustained politico-military operations in at least one other relevant region of the globe beyond its own on a level similar to the most powerful state in the system (44).

Layne disagrees with the requirement that great powers have power-projection capabilities. Instead, he prefers to define great power solely according to whether a state has the capability to defend itself. Let me start by noting that, despite Layne’s rhetoric – labeling my definition of great power “a-historical,” “outlier,” and “theory-saving” – definitions are neither right nor wrong, merely more or less useful. The definition of great power I laid out in Theory of Unipolar Politics is useful to understand contemporary world politics; Layne’s, not so much.

The key novelty of the post-Cold War world is that one country, the United States, has unparalleled power-projection abilities and can therefore intervene militarily in any other region of the world without having to worry too much about the preferences of any other powers outside that region. For example, when Washington decided to invade Afghanistan or Iraq in the early 2000s, did U.S. policy-makers have to worry long and hard about how Beijing would react? Or, more recently, when shaping U.S. policy in the Ukraine crisis, did Washington elites fret about possible Chinese opposition to their preferences? Were U.S. decision-makers ever afraid that Beijing would use its military capabilities to counter U.S. preferences in the Middle East or Eastern Europe? No. The reason is simple: China does not possess the ability to engage in prolonged politico-military operations beyond East Asia and so any words of caution that Beijing might issue against U.S. military intervention elsewhere are largely vacuous in terms of their immediate military impact.

This does not mean that Washington is immune to Chinese preferences. As I argue in Theory of Unipolar Politics, China’s vast economic power gives it the ability to invest in added military capabilities if it so wishes, such that one day it may well be able to deter or thwart U.S. intervention in the Middle East, Europe, Africa, or even the Western Hemisphere. In that long-term sense, Chinese preferences do influence U.S. policies, as they should. But if push comes to shove and U.S. leaders decide it is in the country’s best interest to intervene militarily anywhere outside East Asia, there is little Beijing can do in the short term to deter or defeat U.S. military power.

The relative freedom of military action the United States enjoys stands in contrast to previous eras, in which two or more great powers were able to intervene militarily in regions other than their own. For example, during the “Scramble for Africa” of the late nineteenth and the early twentieth centuries, a great power such as Britain, France, or Germany, when considering its Africa policy had to take into consideration the interests of the other great powers, which could also project military power over the African continent. More recently, U.S. Cold War-era policy in, say, the Middle East or Southeast Asia, was heavily influenced by Soviet interests, because Washington expected Moscow to react to U.S. action in those regions, and the Soviets could, if necessary, back-up their interests with military action.

To capture the difference between these two basic structures of world politics, one needs a definition of great power that incorporates power-projection capabilities, such as the one I use in the book. Layne’s view, in contrast, is that the contemporary world is best understood by ignoring these differences and focusing instead on how China and the United States have roughly similar defensive capabilities. Again, definitions are neither right nor wrong, only more or less useful. Layne’s definition is, I think, as good as any for understanding peace among the most powerful states on earth today. The fact that several states possess survivable nuclear arsenals and, therefore, have commensurable defensive capabilities is, I agree, an important aspect of contemporary world politics; and one captured by Layne’s preferred definition of great power. Layne’s definition does not, however, capture the equally important fact that no state can match U.S. conventional power projection capabilities. So the definition I employed in Theory of Unipolar Politics is analytically superior to Layne’s, as it allows us to capture both (i) the difference between the states that can defend themselves and those that cannot, on which Layne’s definition focuses, and (ii) the unequalled ability to project power possessed by the United States, which Layne prefers to ignore.

After criticizing the role I attribute to military power projection, Layne chastises Theory of Unipolar Politics for devoting insufficient importance to economic power in its definition of great power. In his view, possession of economic capabilities on a par with the most powerful states in the world appears to be sufficient to make a great power. This criticism stems directly from Layne’s signature argument, which he has made since at least 1993: that the rapid growth of the Chinese economy has led to the end of the U.S. ‘unipolar moment,’ making the world bipolar.[77] Discussing the consequences of the Chinese economic boom, Layne characterizes China as competing “with the U.S. for regional hegemony in East Asia,” pointing out that the “dynamics of the Sino-American competition illustrate the problems with Monteiro’s definition of great power status.” Portraying Theory of Unipolar Politics as dismissive of the importance of China’s economic growth, Layne concludes that my view is “an Ivory Tower perspective on the implications of China’s rise – not one that reflects the real world concerns of U.S. policymakers.”

But a careful reading of Theory of Unipolar Politics reveals that, despite Layne’s claims to the contrary, I devote a great deal of attention to China’s rise and its impact “on the U.S. role as the international system’s unipole.” Namely, China’s economic rise gives Beijing the economic clout necessary to balance against the United States if it so wishes. Therefore, I argue in the book, Washington must take China’s interests into account if it wishes to maintain its military power preponderance. When Layne calls Theory of Unipolar Politics a book that “shrugs off the implications of China’s rise,” he ignores the distinction between definition and argumentation. I define great power – and therefore unipolarity – in military terms. Economics only matters in that to be a great power a state cannot have an economy that is vastly weaker than the largest economy on earth, otherwise it would lack the means to build military capabilities on a par with the most powerful state in the system. So, by definition, the economic rise of China has no immediate impact on the number of great powers. At the same time, I argue in Theory of Unipolar Politics that China’s economic rise constrains the United States in its choice of grand strategy – and the freedom with which it uses its military power – if it wishes to prolong its conventional power preponderance. So, pace Layne, my argument places the consequences of China’s economic rise front and center. As I wrote in the book’s concluding sentence, “unparalleled military power requires unequalled self-restraint” (232). Such self-restraint would not be necessary if no other state had the economic capability to build a military that matches the U.S.’s.

Furthermore, even if China were currently engaged in a military contest “with the U.S. for regional hegemony in East Asia,” this would not undermine my view that the world is unipolar – nor, for that matter, would it call into question any of the other arguments in Theory of Unipolar Politics. Competing for regional hegemony in Asia is not the same as acquiring sufficient extra-regional power-projection capabilities to end U.S. global conventional power preponderance. In the extreme, even if the United States pulled out of East Asia entirely – an obviously negative outcome from the perspective of U.S. interests and those of its allies in the region, and a momentous transformation in world politics in itself – this would still not mean the end of unipolarity. Washington would remain able to determine its military strategy in other regions of the globe without fearing a military reaction from China.[78] As long as China is unable to engage in prolonged politico-military operations in at least one region beyond its own, the world remains unipolar regardless of the balance of power in East Asia.

Before moving on, let me note that the historical example Layne uses to support his criticism – the Soviet Union during the early Cold War – does not in any way present problems for my definition of great power, or for the view that today’s world is unipolar. Layne claims that the Soviet Union lacked power projection capabilities beyond its own region between 1945 and the mid-1960s, so that my definition of great power would require us to “re-write diplomatic history” and conclude that the early Cold War had not been bipolar because the USSR was not a great power. Since this is clearly “wrong,” Layne concludes it must be that my definition is inadequate.

Contrary to what Layne writes, the Soviet Union had since the onset of the Cold War the ability to project power beyond its own region. In fact, after the rapid U.S. demobilization that followed the end of World War II, the balance of conventional military power favored the Soviets in most regions of the world beyond the Western Hemisphere.[79] The Harmon Committee, reporting in May 1949 on the consequences of a hypothetical U.S. attack on the Soviet Union, noted that “the capability of Soviet armed forces to advance rapidly into selected areas of Western Europe, the Middle East, and the Far East would not be seriously impaired.”[80] By the mid-1950s, the Soviet ability to project power over the Middle East was unquestionable, leading the United States to act with great prudence. In 1956, for example, during the Suez Crisis, Moscow threatened to retaliate militarily against Britain, France, and Israel for their invasion of Egyptian territory. Conscious of the possibility of Soviet military action – and of the possible expansion of Soviet military influence in the region by creating alliances with Israel’s enemies – the United States urged its allies to pull back.[81] Clearly, Soviet ability to project power over these regions was on roughly the same league as that of the United States, making both into great powers according to my definition.

At the same time, Layne points out that, since the United States represented over half of the world’s economy in the immediate aftermath of World War II, “there is a far stronger argument that 1945-49 was the United States’ first ‘unipolar moment’” (Layne’s emphasis). In fact, this claim follows directly from Layne’s own views on the role of economic power in defining great-power status. My definition, by making economic power a necessary but insufficient condition for great-power status, does not support Layne’s idiosyncratic view. The definition I used in Theory of Unipolar Politics is entirely compatible with the consensual view that the early Cold War was a period of bipolarity.

In sum, the historical example Layne invokes to attack my view that the world is unipolar, when properly understood, supports this view while undermining Layne’s criticisms. First, the fact that the Soviets were considered a great power in the early Cold War despite U.S. economic preponderance demonstrates that relative economic power is not all that matters when determining which countries are great powers. This undercuts Layne’s criticism of what he sees as my disregard for economic power; and it supports my claim that today’s world is unipolar. Second, the fact that the Soviets did possess power projection capabilities during the early Cold War demonstrates that these capabilities are routinely factored into considerations about which countries are great powers. This undercuts Layne’s criticism of my inclusion of power-projection capabilities in my definition of great power, as well as his preference for defining great power based solely on defensive capabilities; it also supports the view that today’s world is unipolar.

Although he does not disagree with my view that the world is unipolar, Jeffrey Taliaferro questions the way I categorize other, less powerful states. Taliaferro criticizes my distinction between major and minor powers, which revolves around whether a state possesses the capability to defend itself against the most powerful states in the world. Specifically, he questions my decision, based on this definition, to include North Korea in the ranks of major powers despite its economic weakness, while excluding “non-nuclear armed states that nonetheless have large economies and sizable conventional military capabilities and that play pivotal roles in their respective regions, such as Germany and Japan” or even Iran from major-power ranks.

As Taliaferro points out, the distinction I make between major and minor powers – whether a state possesses “a plausible chance of avoiding defeat in an all-out defensive war against the most powerful state in the system” – is arbitrary. Furthermore, it results in some awkward bedfellows. Japan, the world’s third largest economy, is categorized as a minor power alongside the island nation of Nauru. North Korea, whose economy, as Taliaferro says, “is in shambles,” features alongside China, the world’s second economy, as a major power. While writing Theory of Unipolar Politics, I considered more complex typologies that would enable me to do away with these counterintuitive classifications. But I realized that for my purposes – to study the security effects of a preponderance of conventional military power in a nuclear world – this simple distinction between great, major, and minor powers worked best. It imposes the lightest conceptual structure on the world, while capturing the two key differences on which I wanted to focus: that between states with and without commensurable power projection capabilities, and that between states with and without robust defensive capabilities. For the purposes I had in the book, all other categories were distinctions that did not make much of a difference.

At the same time, I recognize that for studying different questions my typology may be overly simple. As Taliaferro argues, economic power might play a more important role in defining a major power. After all, I make economic power a necessary condition for great-power status. It might be useful to consider also a threshold of economic power as necessary for major-power status. For example, if no minor powers in a region have an economy that might enable them to ascend to major-power status, the unipole might be less constrained acting in that region than it would be otherwise. On balance, I decided that it was preferable to stick with the more bare-bones definitional apparatus. But I have nothing against others reshaping my typology in order to investigate different questions.

Furthermore, Taliaferro points out that states might have the ability to deter any aggression even without possessing nuclear weapons. Here, I should note that Theory of Unipolar Politics does not classify states based on whether they are nuclear. Rather, I define major powers as the states that have “a plausible chance of avoiding defeat in an all-out defensive war against the most powerful state in the system” (44). I then operationalize this notion as possession of nuclear weapons because that seems the most straightforward way of doing it in today’s world. Perhaps, as I discuss briefly in the Conclusion to the book, technological advances will one day render nuclear weapons obsolete. If that happens, the nuclear threshold would no longer be relevant for major-power status. At the same time, other advancements in the technology of violence might allow some states to ascend to major-power status without having nuclear weapons. These are interesting possibilities for future research. They do not, however, impact upon the basic logic of unipolarity I laid out in the book.

***

I now turn to the reviewers’ criticisms of the arguments I made in Theory of Unipolar Politics about the potential durability of a unipolar world. Unsurprisingly, given that these arguments engage the liveliest scholarly debate on post-Cold War world politics, the reviewers focus most of their attention on this section of the book. They make three broad points: that Theory of Unipolar Politics’ assumption that states privilege the goal of survival over all other aims is incorrect; that its argument on how the nuclear revolution alters the logic of balancing is unsound; and that its analysis of how the unipole’s grand strategy impacts the odds of balancing is misguided.

Before I turn to these specific criticisms, let me note that they largely mirror the existing debate on the durability of a unipolar world. On one side, primacists like Beckley argue that U.S. military power will remain unparalleled for the foreseeable future because of its preponderance in other, so-called latent forms of power – economic, technological, etc. On the opposite side, declinists like Layne argue that U.S. military power will soon be challenged by China because of China’s rise in these latent forms of power. They agree on the theoretical view that once a state’s latent power rises, its military power is sooner or later bound to rise too. Where they disagree is on their assessment of empirical trends in latent power. Whereas primacists such as Beckley see U.S. preponderance of latent power to be long lasting, declinists such as Layne believe it is well-nigh over. This leads both primacists and declinists to resist the key move I made in Theory of Unipolar Politics, which is to re-center the debate from the trajectory of latent power to the causal (balance-of-power) logic that leads states to convert latent into military power. This is the fundamental difference between the arguments I laid out in Theory of Unipolar Politics and those of its critics. For my critics, the interesting action is in the trajectory of relative latent power – in demographic, economic, and technological trends. Military power is, for them, merely an afterthought, a byproduct of growth in these other domains. My view is that IR theorists – and IR scholars more generally – are not well equipped to gauge the likely future trajectory of relative latent power among the world’s most powerful states. To the contrary, IR theorists face a comparative disadvantage vis-à-vis economists on this question. Therefore, we do our discipline – and the policy world – a disservice if we maintain our focus on the sources and likely trajectory of China’s and the United States’ latent power. Our focus should be on the political consequences of this trajectory, among which is the possibility of U.S.-China military competition. It is on these consequences that Theory of Unipolar Politics focuses, and it is in part for this re-centering that the reviewers criticize it. So, on to their criticisms.

To begin with, both Beckley and Layne criticize my assumption that survival is the primary motivation of states. According to Layne, “[e]ven when their survival is assured, the pursuit of other objectives can cause security competitions, and even war,” so that “the quest for wealth, power, and status will generate military competitions between rising powers and the unipole.” Along similar lines, Beckley questions my decision to prioritize survival as a state goal, writing that this “is really a hypothesis that remains to be demonstrated, and contradicts the traditional realist view that states’ ambitions grow as their material resources expand.” Is there a problem with assuming that states privilege survival as a goal? Is my assumption of the priority of state survival over other goals the driving factor in Theory of Unipolar Politics’ argument that great-power competition is avoidable?

Perhaps ironically given these criticisms, I assumed that states privilege survival over other goals in order to be consistent with most existing balance-of-power theories, so that our focus could turn to the differences between Theory of Unipolar Politics and these theories, which, in my view, lies elsewhere, specifically, on my argument on the effects of the nuclear revolution, on which more later. So the first thing to note here is that this assumption is emphatically not responsible for the conclusions I reach in Theory of Unipolar Politics about the potential durability of a unipolar distribution of power. Others have started from the same assumption and reached different, sometimes antithetical conclusions. In what is perhaps the most puzzling comment in his entire 11,000-plus-word review of Theory of Unipolar Politics, Layne quotes Kenneth Waltz – who wrote that “[o]nly if survival is assured can states safely seek such other goals as tranquility, profit, and power”[82] – as evidence that I miss an “important point: for states, survival is not an end, it is a means to other ends.” Waltz and I share the same assumption. We both believe that survival is a prerequisite for other state pursuits and that, therefore, states will care first and foremost about their survival.[83] Even John Mearsheimer, in his Tragedy of Great Power Politics, the ur-text of offensive realism, shares the assumption that “survival is the primary goal of great powers. … Survival dominates other motives because, once a state is conquered, it is unlikely to be in a position to pursue other aims.”[84] Yet, the causal logic he develops from this assumption (together with others) leads him to conclude that U.S.-China geopolitical competition is hardly avoidable. Clearly, the priority of state survival among state goals is not responsible for Theory of Unipolar Politics’ more optimistic view on the prospects of U.S.-China accommodation. Since this assumption is compatible with any view on the odds of great-power competition, I decided to keep it in order to minimize the differences between my assumptions and that of the most prominent existing balance-of-power theories. So when Layne objects that my theory rests “on some pretty heroic assumptions,” I must disagree. In truth, my assumptions are the usual garden-variety assumptions shared with a wide range of balance-of-power views, including the ones that predict the continuation of aggressive balancing. There is nothing heroic about them.

This leads me to a second point. Existing balance-of-power theories often distinguish between revisionist and ‘security-seeking’ states. One of the goals of IR theory at least since Robert Jervis highlighted the “security dilemma” has been to show how conflict may emerge among security-seeking states.[85] If we assume that states are revisionist, then showing that conflict can follow is a somewhat more trivial conclusion. Beckley’s and Layne’s criticism of Theory of Unipolar Politics’ assumption that survival is the fundamental motivation of states is underpinned by their belief that states – particularly powerful ones – will be inherently revisionist. This is explicit in Layne’s claim that “as rising great powers become wealthier, their political ambitions increase” – a claim echoed by Beckley. But if one assumes that states are intrinsically revisionist – and ignores, as both Beckley and Layne do, the fact that war is costly and that most of the times a peaceful agreement that is Pareto-superior to fighting is available – then competition and conflict are indeed very likely to ensue. This is why it is important to be clear about one’s theoretical assumptions. Assuming, as Beckley and Layne urge me to do, that states may privilege other goals over survival and that as their power rises so will their geopolitical ambition, would have led me in the direction of concluding that great-power competition would necessarily recur. But this would not be an interesting theory, as the analytic work of supporting this conclusion would have been borne entirely by its assumptions, not by its causal logic. In contrast, Theory of Unipolar Politics concludes that, in a world of security-seeking states, great-power competition may ensue or not depending on other factors: the cost of war (which is greatly affected by the nuclear revolution) and the strategic choices of the unipole. Given the compatibility of the survival assumption with both cooperative and competitive outcomes, the reviewers’ criticisms of these other factors are, I believe, more interesting. I now turn to them.

Both Beckley and Layne oppose the view that the nuclear revolution puts an end to conventional balancing – a view they ascribe to Theory of Unipolar Politics, and which Layne claims reveals my “shaky grasp of nuclear strategy.” As they note, the argument on the consequences of the nuclear revolution for balancing efforts is at the core of Theory of Unipolar Politics. So let me start by laying out precisely the role played by the nuclear revolution in the book’s argument on the potential durability of a unipolar world. As will soon become clear, the reviewers characterize my views in an imprecise manner.

In the book, I made a two-step argument connecting the nuclear revolution with the prospects of conventional balancing in a unipolar world. First, in keeping with the general nuclear revolution argument famously made by Kenneth Waltz and Robert Jervis, I argue that any military conflict between nuclear powers with an assured retaliatory capability entails a non-negligible risk of escalation to the nuclear level.[86] Then, I argue that given this escalation danger, under certain conditions the nuclear revolution will stop conventional balancing; under other conditions, it will not. Indeed, one of the goals of the book was to lay out the conditions under which each of these outcomes – balancing versus a durable preponderance of power by one state – is likely. When a nuclear preponderant power tries to constrain the economic growth of another nuclear state, I argue, the target of this containment strategy is likely to balance conventionally. Likewise, when a nuclear preponderant power attempts to revise the status quo in a region inhabited by another nuclear power in its own favor, that other nuclear power is also likely to balance conventionally. Still, when a nuclear state that possesses a preponderance of conventional power accommodates the economic growth of a conventionally weaker nuclear state and supports the military status quo in its region, I argue, this conventionally weaker nuclear state will have no security incentive to continue to balance conventionally, making the preponderance of conventional power of the accommodating state durable. Put differently, if the preponderant power fulfills the two conditions laid out above, the conventionally weaker state will only balance if it does not privilege survival over all other goals – if it is an intrinsically revisionist state – or if it is not rational. Otherwise, in a world of rational security-seeking states, the nuclear revolution makes a preponderance of conventional power potentially durable.

Beckley and Layne engage this argument in different ways. While Beckley focuses on evidence from contemporary U.S.-China relations, Layne attempts to provide a theoretical criticism of my argument, while also supporting it with historical examples. I start with the latter and save contemporary world politics and the military dimension of U.S.-China relations for the end of this section.

Layne’s criticism of my theory is deeply flawed. He starts by criticizing the first step in my argument – on the consequences of the omnipresent possibility of escalation between nuclear powers – by supplying what he considers is “too much evidence” against it. For him, my argument that, since military competition over secondary goals might lead to escalation, rising economic powers may eschew conventional balancing “brushes aside most of what we know – theoretically and empirically – about the rise of great powers.” What are the historical examples that warrant this conclusion? Layne begins by invoking the period between 1945 and 1949, which he labels “the United States’ first unipolar moment,” and in which “notwithstanding the U.S. nuclear monopoly … the Soviet Union competed hard to balance U.S. power.” He sees this as historical evidence against Theory of Unipolar Politics’ claim that “in a unipolar nuclear world, Mutual Assured Destruction (MAD) would prevent rising powers from engaging in conventional military competition with the unipole.” How does a period marked by a U.S. nuclear monopoly count as evidence against my claims on the consequences of MAD? One wonders. Furthermore, Layne invokes Russian opposition to NATO expansion after the Cold War as another example that cuts against my claim that the nuclear revolution obviates the need for conventional balancing. But, as should be clear by now, I argue for this pacifying effect of the nuclear revolution only if the unipole refrains from trying to revise the status quo in its own favor in the regions inhabited by other nuclear powers. So, in fact, my theory predicts that Russia would oppose NATO expansion during the Cold War. Again, Layne’s example supports my theory. Finally, Layne invokes examples of military clashes between nuclear powers (the Kargil War and the 1969 Ussuri River Sino-Soviet clashes) and of wars fought between nuclear and non-nuclear states (Chinese intervention in the Korean War; the 1973 Yom Kippur War) as telling cases that disprove my theory. Starting with the latter, it should be clear that wars involving non-nuclear states have no bearing in adjudicating the effects of the nuclear revolution, which focuses on relations among nuclear states. I leave it to readers to decide whether the Kargil War and the 1969 Ussuri River Sino-Soviet clashes support Layne’s view that “there is too much evidence” against my theory. I obviously disagree.[87]

After rebutting my claim that the possibility of nuclear escalation makes states more prudent, one would expect Layne to turn to the conditional aspect of the claims I make in the book. He does not. Instead he construes a straw-man version of my argument according to which I claim that “in a unipolar world it is irrational for any rising power to engage in a conventional challenge to the unipole’s privileged position in the international system” and that “[i]n a nuclear world, conventional wars involving nuclear armed powers will not occur because of the risk of escalation.” Theory of Unipolar Politics makes no such categorical arguments. Instead, these statements apply only when the unipole abides by the strategic conditions laid out above. If the unipole does not abide by these conditions – if it attempts to contain the economic growth of nuclear powers or to revise the status quo in their regions in the unipole’s favor – then the long-term survival of nuclear powers will be at risk and will engage in conventional competition with the unipole in order to boost their security. In a nutshell, my argument is that in a nuclear world of security-seeking states in which one has a preponderance of conventional power, the level of great-power competition will be determined by the grand strategy this preponderant power implements. So Layne’s criticism of my views on the nuclear revolution is intimately connected with his – and the other reviewers’ – criticisms of my views on the consequences of the unipole’s grand-strategic choices. Let me turn to these.

The reviewers offer three criticisms of Theory of Unipolar Politics’ analysis of how the unipole’s grand strategy impacts the odds of balancing. First, Layne argues that my views on the effects of different strategies are mutually contradictory. Second, Layne claims that a rational major power should not balance in response to an attempt on the part of the unipole to contain its economic growth or revise the status quo in the major power’s region. Finally, Taliaferro criticizes Theory of Unipolar Politics for “the absence of a causal mechanism for grand strategic adjustment by the unipole.”

Let me start by addressing Layne’s charge that Theory of Unipolar Politics includes some mutually contradictory arguments on the effects of the unipole’s strategy on the durability of its power preponderance. I argue in the book that, in a nuclear world, a strategy of defensive accommodation (i.e., a military strategy of defensive dominance and an economic strategy of accommodating major powers’ growth) would allow for the maintenance of the unipole’s power preponderance. I also argue that any change to this strategy – implementing a military strategy of either offensive dominance or disengagement; implementing an economic strategy of containment – would prompt major powers to balance conventionally against the unipole. Layne claims that these two arguments are contradictory. He argues that my argument on the consequences of offensive dominance and economic containment “collides head-on” with my sanguine view on the pacifying effects of the nuclear revolution. Layne concludes that “Monteiro can’t have it both ways. If the nuclear revolution prevents big wars when the unipole adopts a defensive dominance strategy, war equally must be ruled out even if the unipole follows an offensive dominance strategy.” Furthermore, if one takes my view of the nuclear revolution seriously, Layne proceeds, one would realize that any attempt to balance on the part of major powers would lead the unipole to “engage in preventive war to maintain its dominant position in the international system.”

This criticism indicates another misreading of Theory of Unipolar Politics on Layne’s part. If survival is the primary goal of states, they will balance when their survival is at stake and will avoid balancing when their survival is ensured. If the unipole maintains the status quo in a major power’s region and allows for its economic growth, the major power has its survival virtually ensured, both in the short- and the long-term. If, however, the unipole attempts to revise the status quo in the major power’s region in the unipole’s own favor or attempts to constrain the major power’s economic growth, then the major power’s survival will be threatened – in the short- or long-term, respectively. Under these conditions, and only under these conditions, the major power will balance. There is no contradiction here. When its survival is ensured by the possession of nuclear weapons and the unipole’s non-threatening strategy, a major power will eschew additional conventional balancing. When its survival is threatened by the unipole’s strategy, a major power will balance in an attempt to make it potentially more risky and costly for the unipole to continue to pursue its strategy. In other words, when the unipole threatens a major power’s survival, the major power will no longer rule out the possibility of war – even in the nuclear age – because peace is not allowing it to secure its key goal, survival.

Furthermore, should the major power then engage in a balancing effort, as long as the unipole maintains its nuclear deterrent and the major power is unable to constrain its economic growth, the unipole’s own survival would not be threatened. So there is no reason to think, as Layne does, that in this situation the unipole would be tempted to launch a preventive nuclear war. Doing so would, indeed, to use the quip by German Chancellor Otto von Bismarck that Layne quotes, be “committing suicide for fear of death.”

Layne’s second criticism of my treatment of the relationship between strategy and the odds of an enduring preponderance of power is that, should the unipole implement a military strategy of offensive dominance or an economic strategy of containment, even then a major power’s rational response would be to wait and see, not to balance. As Layne argues, a containment strategy “would almost certainly require a long time to work, and many things could derail that policy long before it accomplished its intended purpose,” so that rather than risking war, “a major power that was the object of the unipole’s economic containment policy would be better off to play for time.”

This is befuddling. Layne has devoted his career to arguing that rising powers will balance under any conditions, even if facing the most benevolent unipole, so that a systemic preponderance of power is never long lasting.[88] Here, however, Layne argues that rising powers should not balance even if the unipole uses all the tools in its policy kit to try and stymie their ability to ensure their own survival and generate wealth. Surely, Layne cannot have it both ways: either major powers will never balance or they will balance at least when their survival is at stake. In my view, if a major power’s strategic environment is made worse by the unipole’s actions, then it is in the major power’s self-interest to balance immediately rather than wait and see its relative power and position gradually decline as a result of the unipole’s aggressive military and economic strategies.[89]

Finally, Taliaferro criticizes Theory of Unipolar Politics for “the absence of a causal mechanism for grand strategic adjustment by the unipole.” In his view, Theory of Unipolar Politics does not account for the “conditions under which the unipole might switch from a grand strategy” to another, because it fails to incorporate domestic politics into the strategic calculus of the unipole. For example, Taliaferro notes, any account of “why the George W. Bush administration not only embarked upon a strategy of offensive dominance in the greater Middle East after the 9/11 terrorist attacks, but targeted Iraq, which was clearly a recalcitrant minor power in deep relative decline, instead of Iran, a recalcitrant minor power in relative ascendancy,” requires incorporating unit-level variables into my theory.

This is an important point, though only partially correct. The way Theory of Unipolar Politics accounts for strategic choice is by laying out the cost-benefit calculation the unipole will perform in order to determine its grand strategy. Each strategy, as I outline above, may entail conflict and competition costs. I argue that the unipole will implement the strategy that yields greater benefits net of these costs. In other work (co-authored with Alexandre Debs), I have argued that the U.S. decision to invade Iraq resulted from the lower tolerance for uncertainty about whether Baghdad was developing nuclear weapons in the aftermath of the 9/11 attacks.[90] Put in terms of the theory in Theory of Unipolar Politics, 9/11 increased the costs the United States expected to pay by continuing to implement its strategy of defensive dominance in the Middle East, leading Washington to decide for a shift towards a strategy of offensive dominance, resulting in the invasions of Afghanistan and Iraq. This strategy did not entail a competition cost for the United States – i.e., it did not prompt any states to balance against the preponderance of U.S. conventional military power – because no state in the Middle East has the economic might necessary to become a great power. After a decade of entanglement in the region, and given the higher-than-expected costs of conflict it was paying, the United States decided to scale down its military operations in Iraq and Afghanistan, shifting back to a strategy of defensive dominance in the Middle East.

Despite the fact that Theory of Unipolar Politics includes “a causal mechanism for grand strategic adjustment by the unipole,” Taliaferro is right to point out the absence of unit-level variables – or, for that matter, ideational variables – in this causal mechanism. In my view, the variables I include are sufficient to provide a succinct account of the historical record. Taliaferro may disagree and call for a fuller account; one that incorporates the policy and ideological preferences of particular U.S. groups. I am sympathetic to this sort of friendly amendment, and hope that other scholars will take up the task of expanding on Theory of Unipolar Politics to include these factors.

After having engaged the reviewers’ theoretical criticisms of my views on durability, let me turn briefly to their disagreement with my view of contemporary U.S.-China relations. Layne argues that China is “engaged in an impressive military buildup” and “compet[ing] with the U.S. for regional hegemony in East Asia.” He takes this to be evidence against the views I expressed in Theory of Unipolar Politics, because in “East Asia today we see two of the most important hallmarks of great power competition: a struggle for regional supremacy, and an ongoing power transition.” Though qualifying the overall geopolitical situation differently, Beckley concurs that “China aims to bolster its military capabilities and eventually redraw the geopolitical map,” noting that China’s actions “resemble actions taken by the United States in the late nineteenth century.”

Nowhere in Theory of Unipolar Politics did I deny that China is engaged in an “impressive military buildup” aimed at being better able to pursue its secondary interests in East Asia, including being able to deny the United States the relatively free hand it has enjoyed in the region since the end of the Cold War. In fact, Theory of Unipolar Politics argues that

China is growing economically and boosting its regional military capabilities, as major powers do. The issue is whether this means that China will acquire military capabilities that would allow it to project power beyond its region in a way commensurable with the United States. For this question, data on China’s recent trajectory is irrelevant. As William Wohlforth, whose work places him among the foremost primacists, has put it in his incisive rebuttal of Layne’s argument that the trajectory of China up till the present moment foretells the end of U.S. power preponderance:[91]

The recent decline in the United States’ economic fortunes does not vindicate any prediction made by any balance-of-power realist, has no implications for any theoretical proposition about the functioning of a unipolar system, and has not caused a structural shift to bi- or multipolarity. Things can be made to seem otherwise only when scholars use inconsistent measures of capabilities, do not define terms with precision, forward inherently unfalsifiable arguments, and fail to clarify causal mechanisms.[92]

I could hardly put it better. China has not attempted to reestablish – much less has it achieved – parity vis-à-vis the United States in terms of its power-projection capabilities. Beckley and Layne’s logic of argumentation is to say that China’s military has developed from (i) being utterly unable to impose significant costs on the United States if Washington decides to intervene militarily in East Asia to (ii) being able to impose costs on U.S. forces in China’s region, so it must be the case that soon China will (iii) acquire sizeable power-projection capabilities, because that is what past great powers did. (They disagree between them on when exactly this will happen, with Layne believing China will be able to reach military parity with the United States much earlier than Beckley foresees.) But whether indeed China will do so depends on one’s view on whether nuclear weapons revolutionized world politics – precisely the question we are trying to adjudicate. My critics’ argument presupposes that nuclear weapons did not revolutionize world politics and then goes on to show that, if you agree with such presupposition, it turns out that China will behave just like any past great power. The problem is that there is no good reason, at least in my view, to disregard the consequences of the nuclear revolution for great-power politics. So expectations about China’s future military investments cannot be formed solely on the basis of China’s past military investments. They require a theory about China’s motivations – what position it is trying to acquire in the international system – and a view on whether nuclear weapons have transformed the dynamics of competition among the most powerful states in the system. Theory of Unipolar Politics provides one such view.[93]

***

I now turn to the reviewers’ third and last set of criticisms, focusing on my account of the sources of conflict in a unipolar world. To begin with, Beckley questions my argument that a preponderance of conventional power aggravates the unipole’s commitment problems, causing conflict. In his view, Theory of Unipolar Politics assumes, wrongly, “that unipolarity generates unique commitment problems between great and minor powers” and, as a result, overestimates “the likelihood of wars between the United States and recalcitrant minor powers.” Beckley acknowledges that, as I argue, minor powers will have trouble committing not to attempt to develop nuclear weapons, in turn making it difficult for the unipole to commit not to attack them. But he argues that these commitment problems are not unique to a unipolar world. Minor powers, according to Beckley, “have strong incentives to acquire nuclear weapons regardless of the global distribution of power.” The unipole, for its part, does not care much about minor powers, and is unlikely to use force against them “because of its manifest lack of interest in going to war over minimal stakes.” In sum, for Beckley, a unipolar distribution of power poses no particular incentives for war between the preponderant power and recalcitrant minor powers.

I agree that commitment problems are a feature of any weakly institutionalized setting, and therefore are always present in world politics. This does not mean they are invariable. To the contrary, certain situations aggravate the commitment problems states face, making conflict more likely.[94] My argument is that unipolarity is one of these situations, because it makes it impossible for recalcitrant minor powers to find a great-power sponsor capable of deterring aggression by the unipole. This absence of a great-power sponsor – a situation I label ‘extreme self-help’ – aggravates existing commitment problems in two ways. First, it increases the expected security benefit recalcitrant minor powers would extract from nuclear acquisition. This makes it more likely that they would want to develop a nuclear weapon, making it harder for them to commit not to do so. Second, it eliminates the risk that a conflict against a recalcitrant minor power might escalate into a great-power war by eliciting a reaction from the minor power’s sponsor. This lowers the expected cost of a war between the unipole and a recalcitrant minor power, making it harder for the unipole to commit not to use force to prevent proliferation.[95] Taken together, these two factors constitute a pathway to conflict that is more likely to result in war when there is no systemic balance of power.

How could this be if in practice, as Beckley points out, “no nation has started a new nuclear weapons program since the emergence of unipolarity in 1991.” By the time the Cold War ended, most if not all recalcitrant minor powers – Iran, Iraq, Libya, and North Korea – already had active nuclear programs. Of these, only North Korea, which possessed a great ability to inflict costs on South Korea (a U.S. ally) in case of a military conflict, managed to acquire nuclear weapons. Iraq was attacked by the United States in 2003 with the explicit purpose of thwarting the country’s suspected proliferation efforts. Libya gave up its program shortly thereafter under the implicit threat of military action. Iran has recently reached a negotiated freeze to its program as well, having been under explicit threat of U.S. military action if a deal were not reached.[96] Overall, then, this mechanism accounts for one of the major post-Cold War conflicts in which the United States has engaged: the Iraq War. As Iraqi leaders had already made clear in 1991 after their military forces were evicted from Kuwait by a U.S.-led coalition, U.S. action was facilitated by the absence of an Iraqi great-power sponsor.

Is one war in a quarter century a lot? The purpose of the claims I make in Theory of Unipolar Politics on the sources of conflict in a unipolar world is not to argue that unipolarity is more conflict-prone than other types of international system. Such comparisons are, I believe, futile. Wars are relatively rare events, so any relative claims are difficult to test with the available data. Instead, I aimed at developing the causal logics that are likely to lead to conflict in a unipolar world, undermining the view that a preponderance of power is a clear force for peace. In my view, the preventive dynamics surrounding nuclear proliferation efforts are likely to play an important role in generating conflict between an engaged unipolar power and recalcitrant minor powers.

In contrast with Beckley’s optimistic view of the effect of unipolarity on peace, Layne seems to agree with my description of a unipolar world as prone to war. For Layne, however, the account of the causes of frequent post-Cold War conflicts involving the United States that I included in Theory of Unipolar Politics is wrong-headed. In Layne’s words, although Theory of Unipolar Politics “provides an impressive theoretical gloss to the argument that unipolarity is not peaceful, there are other equally important explanations for this phenomenon.” What are they? First, Layne lays out his own “unipole’s temptation” argument, according to which the lack of a peer competitor will result in a unipolar power being “easily lured into overseas military adventures,” initiating “many wars,” and using its military power “promiscuously” and “conspicuously.” Second, Layne claims that conflict is likely to be caused by “the very nature of a unipole’s power preponderance, [which] predisposes it to fight wars in order to maintain its leading position in the international system.” Finally, Layne claims that a unipole must be willing to extend deterrence to other states in order to avoid nuclear proliferation, that such extended deterrence efforts require making threats credible, and that “[f]ighting wars against small powers in the periphery is an important mechanism for bolstering the unipole’s reputation for credibility.” Layne concludes that “the unipole will beat up on small states” in order to send “a clear Dirty Harry-like (the tough San Francisco detective memorably portrayed by Clint Eastwood) message to any major power that might be thinking of mounting a challenge by ascending to peer competitor status: ‘go ahead, make my day’;” or, “as (in the TV series The Sopranos) Mafia boss Tony Soprano was told by his chief henchman, Paul Walnuts, with respect to the head of a rival family, ‘clipping the guy is always an option.’”

Layne’s claim that war will be caused by the “unipole’s temptation” to initiate “overseas military adventures” is closely related to my own argument that, under particular strategic circumstances, a unipolar power will implement a military strategy of offensive dominance. The main difference between his view and mine on this point is that while I specify the conditions under which this strategy will be the optimal choice for the unipole, Layne leaves those conditions unspecified. Likewise with Layne’s claim that conflict will be caused by “the very nature of a unipole’s power preponderance.” What is the causal factor accounting for variation in the level of conflict if war is caused by the unipole’s “very nature,” presumably a constant? This sort of underspecified claim is unfalsifiable, failing to fulfill one of the basic conditions that make an argument scientific. Finally, Layne’s claim that reputational concerns will prompt the unipole to fight numerous conflicts is a plausible alternative to the argument I lay out in the book. This reputation-based argument has been put forth most clearly by Todd Sechser.[97] But in Sechser’s rigorous logic – which is compatible with the argument in Theory of Unipolar Politics – war happens not because the unipole wants to “beat up on small states.” After all, no state, not even a powerful one, wants to fight. War is costly and destroys resources the unipole might appropriate in a peaceful settlement. Therefore, the unipole wants others to make concessions. It is small states that have an incentive to stand up to the unipole’s demands, because they fear that conceding to its demands will lead it to make further demands. If it was not for minor powers having incentives to resist the unipole’s demands in order to establish a reputation for toughness, war would not occur. Their opposition to these concessions is equally responsible for the war. Yet, Layne’s account for why war happens in a unipolar world ignores this strategic dimension. Without it, one cannot provide a coherent account of the causes of war when a systemic balance of power is absent.

Finally, Taliaferro objects to three other aspects of my account of the sources of conflict in Theory of Unipolar Politics. First, in his opinion, the only strategy that would allow the unipole to avoid frequent conflict – disengagement –is empirically implausible. While recognizing that the strategies I delineate are ‘ideal types,’ Taliaferro criticizes my inclusion of disengagement in my analysis of a unipolar world because “the likelihood that any presidential administration in Washington would contemplate, let alone attempt to pursue, such a drastic [global] retrenchment is exceedingly low,” so that “barring a catastrophic economic collapse,” it is hard to see how the United States might “terminate all standing alliances, revoke all security guarantees, and abandon its network of forward military bases.”

I agree with this empirical assessment. It is hard to foresee a set of circumstances that would lead the United States to disengage from the world. My purpose with Theory of Unipolar Politics, however, was to lay out a theory about the working of any unipolar system, and that required the inclusion of a strategy of military disengagement, implausible as it may be in the foreseeable future. Furthermore, even in a world in which disengagement is unlikely to be implemented, Theory of Unipolar Politics highlights two of its important consequences. First, if, as I argue in the book, disengagement leads to significant conflict among major and minor powers, we should be skeptical of calls for U.S. disengagement that present increased peacefulness as one of its likely consequences. Make no mistake, disengagement would spare U.S. forces. But conflict would fester among others in the absence of a great-power presence in their region. Second, Theory of Unipolar Politics highlights how disengagement would lead other powers to balance against each other in a tide that would lift all boats except the U.S.’s, decreasing and eventually erasing the gap in conventional capabilities that today separates the United States from all other countries on earth. As such, disengagement entails a significant competition cost, and this is an important factor preventing U.S. decision-makers from adopting it. Put differently, Theory of Unipolar Politics includes a theoretical account of why, as Taliaferro notes, it is so difficult to imagine any U.S. administration disengaging from the world: the competition costs which this strategy would entail, under current conditions, are greater than the benefit it would present in terms of conflict avoidance.

Second, Taliaferro criticizes my definition of ‘recalcitrant minor power’ – the states most likely to find themselves at war with the unipole – which he sees as incomplete in the absence of any ideational variables. In his view, domestic and ideological factors are necessary to determine which minor powers will become recalcitrant. Without these factors we cannot account for which minor powers become recalcitrant and which, in contrast, decide to accommodate the unipole’s preferences.

I agree. Theory of Unipolar Politics does not include a fully developed argument about which minor powers will become recalcitrant. All it does is point out that when a local rivalry leads the unipole to protect one state at the expense of its regional rival, the state that is left out is more likely to become a recalcitrant minor power (163). I also note that “ideological reasons may increase the proclivity of certain minor powers to confront the unipole,” and that “[r]egimes grounded on ideologies fundamentally at odds with that espoused by the unipole are more likely to refuse to be co-opted” (50). As I note, however, this ideological rationale is not part of the material structure of a unipolar system, on which I decided to focus in Theory of Unipolar Politics. So I opted for not developing these arguments. This does not mean that I am oblivious to the role of ideology in producing conflict. But I opted for keeping my theory as parsimonious as possible, leaving to others the exploration of these ideological dimensions – and of their interaction with a preponderance of conventional military power. In Theory of Unipolar Politics, I built what I think is the barebones theoretical machine necessary to understand the conditions of durability and the forces for conflict in a world with several nuclear powers and a preponderant conventional military power. Others may wish to complement this theory with additional dimensions: ideology, domestic politics, norms, etc. There is nothing wrong with that; in fact, I would encourage and support those efforts. This is not the place for a debate on the merits of theoretical parsimony versus theoretical completeness, but I tend to think that a parsimonious theory is easier to falsify and I value falsifiability higher than completeness, thus my choices in Theory of Unipolar Politics. But reasonable people can reasonably disagree on this, so I can see why Taliaferro would prefer that I do otherwise.

Finally, Taliaferro points out that Theory of Unipolar Politics is unclear on whether recalcitrant minor powers include “transnational terrorist networks that find safe-havens in failed states … or which seize and control territory from states.” As he rightly points out, “since the United States will likely engage in low-level military operations against non-state or quasi-state entities like al-Qaeda, al-Qaeda in the Arabia Peninsula (AQAP), and the Islamic State (also called ISIS or ISIL) for some time to come,” this is not an inconsequential omission on my part.

In Theory of Unipolar Politics, I focused on state actors and eschewed questions about violent non-state actors such as terrorist networks aimed at targeting the unipole or any of its allies. These would come into the purview of the book’s argument only if they were to capture a state, which would then become a recalcitrant minor power. So my answer to this criticism by Taliaferro is to agree that territories – typically part of failed states – that are captured by terrorist networks can indeed be considered recalcitrant minor powers. At the same time, terrorist networks that operate within (but without capturing) states do not fall under the purview of my theory. I acknowledge that they may play an important role in the unipole’s grand strategy – and, indeed, as Taliaferro points out, some of these actors do play a key role in contemporary U.S. strategy. So this may legitimately be seen as a self-imposed limitation of the book.

***

This brings me back to what was my overarching aim in writing Theory of Unipolar Politics: to highlight the role of theory in adjudicating the key debates on unipolarity that we had been trying to settle empirically and, for the most part, without reflecting on the need to revise our theories in light of such a novel historical situation. The only debate that data can settle is that on whether unipolarity was indeed going to be merely a historical moment, as many, including Layne, argued from the early post-Cold War.[98] The Cold War ended a quarter century ago. Not even the most pessimistic doomsayers on U.S. decline believe that China could muster a military power-projection capability comparable with the United States’ – even if that were its “national priority number one,” which it clearly is not – for at least another two decades. This means the unipolar “moment” will be at least as long as the Cold War, probably longer. Clearly, ‘moment’ is a misnomer.

As for the other key debates of the post-Cold War – whether unipolarity is durable and peaceful – no amount of data will settle them any time soon in the absence of a theoretical framework. The question of whether China will make a bid to overturn U.S.-led liberal hegemony and curtail U.S. military freedom of action around the globe will remain empirically open unless and until China makes that bid. The question of whether the U.S. preponderance of conventional military power makes for more or less conflict than existed in previous eras would require us to amass decades, if not centuries, more of data before reaching any conclusions.[99] So looking exclusively at empirical data undermines our ability to say anything useful about how the preponderance of U.S. conventional military power affects the likely course of future world politics, including the prospects for U.S.-China relations and the odds of conflict involving the United States. If, on these questions, we want the owl of Minerva to spread its wings before dusk, we need a theory of unipolar politics.

For allowing me the opportunity to continue to engage these questions, I would like to conclude by expressing my gratitude to Michael Beckley, Christopher Layne, and Jeffrey Taliaferro, who have provided an abundance of thoughtful and provocative comments; to William C. Wohlforth, who graciously introduced this forum; and to the editors of H-Diplo, particularly James McAllister, who shepherded this roundtable throughout its production. It is a distinct pleasure to be included in this forum.

Notes

[1] Kenneth Waltz, Theory of International Politics (Reading, MA: Addison-Wesley, 1917)

[2] Christopher Layne, “The Unipolar Illusion: Why New Great Powers Will Rise,” International Security, 17:3 (Spring, 1993), 5-51. Waltz discussed unipolarity in “Structural Realism after the Cold War,” International Security, Vol. 25, No. 1 (Summer 2000), 5–41.

[3] In “The Emerging Structure of International Politics,” International Security, 18:2 (Fall 1993), 44-79, Waltz discussed the existing structure as altered bipolarity (“bipolarity endures, but in an altered state” 72), and argued assume that the emerging structure would be multipolar, with Japan and Germany becoming normal great powers.

[4] Michael Beckley, “China’s Century? Why America’s Edge Will Endure,” International Security 36/3 (Winter 2011/12), 41-78; and “The Myth of Entangling Alliances: Reassessing the Security Risks of U.S. Defense Pacts,” International Security 39/4 (Spring 2015), 7-48.

[5] For example, see Robert Gilpin, War and Change in World Politics (New York: Cambridge University Press, 1981).

[6] Avery Goldstein, “China’s Real and Present Danger: Now Is the Time for Washington to Worry,” Foreign Affairs, Vol. 92, No. 5 (September/October 2013), p. 140.

[7] Andrew S. Erickson, “Rising Tide, Dispersing Waves: Opportunities and Challenges for Chinese Seapower Development,” Journal of Strategic Studies, Vol. 37, No. 3 (July 2014), 372-402.

[8] Evan Braden Montgomery, “Contested Primacy in the Western Pacific: China’s Rise and the Future of U.S. Power Projection,” International Security, Vol. 38, No. 4 (Spring 2014), 124-126.

[9] Francis J. Gavin, “Same As It Ever Was: Nuclear Alarmism, Proliferation, and the Cold War,” International Security, Vol. 34, No. 3 (Winter 2009/10), pp. 32-35.

[10] Leaving aside the question of how much is ‘much,’ there certainly have been some important theoretical works on unipolarity written since the Cold War’s end. For example, see, Stephen Brooks and William C. Wohlforth, World Out of Balance: International Relations Theory and the Challenge of American Power (Princeton: Princeton University Press, 2008); Ethan B. Kapstein and Michael Mastanduno, eds, Unipolar Politics (New York: Columbia University Press, 1999); Christopher Layne, “The Unipolar Illusion: Why New Great Powers Will Rise,” International Security, 17:3 (Spring, 1993), 5-51; Christopher Layne, “The Unipolar Illusion Revisited: The Coming End of the United States’ Unipolar Moment,” International Security 31:2 (Fall 2006), 7-41; William C. Wohlforth, “The Stability of a Unipolar World,” International Security, 24:1 (Summer, 1999), 5-41. Also, see the World Politics special issue on unipolarity edited by G. John Ikenberry. Michael Mastanduno, and William C. Wohlforth. G. John Ikenberry, Michael Mastanduno, and William C. Wohlforth, “Unipolarity, State Behavior, and Systemic Consequences,” World Politics, 61:1 (January, 2009), 1-27.

[11] Kenneth N. Waltz, Theory of International Politics (Reading, Mass.: Addison-Wesley, 1979). As Monteiro notes, Theory of Unipolar Politics is “mostly a theoretical book. My views build on the traditional of structural theorizing epitomized by Waltz, whose classic work, Theory of International Politics, inspired the book – and quite obviously, its title” (22-23).

[12] For example, the George H. W. Bush administration’s draft Defense Planning Guidance for fiscal years 1994-99 stated that the United States “must maintain the mechanisms for deterring potential competitors from even aspiring to a larger regional or global role.” Quoted in Patrick Tyler, “U.S. strategy plan calls for insuring no rivals develop,” New York Times, March 8, 1992; “Excerpts from pentagon’s plan: ‘Prevent the re-emergence of a new rival’,” New York Times, March 8, 1992. The Clinton administration described the United States as “the world’s preeminent power.” A National Security Strategy of Engagement and Enlargement (Washington, D.C.: White House, February 1995). The George W. Bush administration stated that the aim of U.S. grand strategy is to prevent any other power from “surpassing, or equaling, the power of the United States.” The National Security Strategy of the United States of America (Washington, D.C.: White House, September 2002), 30 (emphasis added). Unsurprisingly, given that its key foreign policy positions are staffed largely by veterans of the Bill Clinton administration, leading Obama administration officials are wedded to preserving U.S. hegemony. The Obama administration has declared that it is “focused on renewing American leadership so that we can more effectively advance our interests” and also that “going forward there should be no doubt: the United States of America will continue to underwrite global security.” National Security Strategy (Washington, D. C.: The White House, May 2010), 1. Also see Hillary Rodham Clinton, “Remarks on United States Foreign Policy,” Council on Foreign Relations, Washington, D.C., September 8, 2010, http://www.state.gov/secretary/rm/2010/09/146917.html.

[13] Layne, “The Unipolar Illusion”; Kenneth N. Waltz, “The Emerging Structure of International Politics,” International Security, 18:2 (Fall 1993), 44-79.

[14] Brooks and Wohlforth, World Out of Balance; Wohlforth, “Stability of a Unipolar World.”

[15] For key works on unipolar stability, and the U.S. strategy of primacy, see Brooks and Wohlforth, World out of Balance; Joseph Joffe, The Myth of America’s Decline: Politics, Economics, and a Half Century of False Promises (New York, W.W. Norton & Company, 2014); Robert Lieber, Power and Willpower in the American Future: Why the United States is not destined to decline (Cambridge: Cambridge University Press, 2012); Joseph S. Nye, Jr., Is the American Century Over? (Hoboken, NJ: John Wiley & Sons, 2015); Stephen Brooks, G. John Ikenberry, and William Wohlforth, “Don’t Come Home, America: The Case Against Retrenchment,” International Security, 37:3 (Winter, 2012/2013); Charles Krauthammer, “The Unipolar Moment,” Foreign Affairs 70:1 (1990/1991), 23-33; For important arguments on unipolar instability, and advocating grand strategic alternatives to U.S. primacy, see Christopher Layne, The Peace of Illusions: American Grand Strategy from 1940 to the Present (Ithaca: Cornell University Press, 2006); Barry R. Posen, Restraint: A New Foundation for US Grand Strategy (Ithaca: Cornell University Press, 2014); Stephen Walt, Taming American Power: The Global Response to US Primacy (New York, W.W. Norton, 2005); Christopher Layne, “From Preponderance to Offshore Balancing: America’s Future Grand Strategy,” International Security 22:1 (Summer, 1997), 86-124; Eugene Gholz, Daryl Press, and Harvey Sapolsky, “Come Home America: The Strategy of Restraint in the Face of Temptation,” International Security 21:4 (Spring, 1997), 5-48; Layne, “The Unipolar Illusion”; Joseph M. Parent and Paul K. MacDonald, “The Wisdom of Retrenchment: America Must Cut Back to Move Forward,” Foreign Affairs 90:6 (November/December, 2011), 32-36, 37-42, 43-47; Christopher Layne, “This Time it’s Real: The End of Unipolarity and the Pax Americana,” International Studies Quarterly 56:1 (March, 2012), 1-11.

[16] See Barry R. Posen, “Command of the Commons: The Military Foundations of U.S. Hegemony,” International Security, 28:1 (Summer 2003), 5-46.

[17] Layne, “The Unipolar Illusion;” Waltz, “The Emerging Structure of International Politics.”

[18] A second variant of unipolar optimism is based on the claim that, because U.S. hegemony is ‘benevolent’ there is no reason why other states would want to balance against the United States. The argument for U.S. benevolence has three prongs. One is that other states have strong incentives to align with the U.S. because they derive important security and economic benefits from American hegemony. Brooks and Wohlforth, World Out of Balance; Stephen G. Brooks and William C. Wohlforth, “American Primacy in Perspective,” Foreign Affairs, 81:4 (July/August, 2002), 20-33. The second – essentially a balance-of-threat argument – is that by practicing self-restraint, demonstrating sensitivity for others’ interests, and acting through multilateral institutions, the United States can allay others’ fears that it will use its hegemonic power for self-aggrandizing purposes. Walt, Taming American Power; Stephen M. Walt, The Origins of Alliances (Ithaca, N.Y.: Cornell University Press, 1997); Michael Mastanduno, “Preserving the Unipolar Moment: Realist Theories and U.S. Grand Strategy After the Cold War,” International Security 21:4 (Spring 1997), 49-88. The third prong is that the United States’ ‘soft power’ – the attractiveness of its ideology and culture – draws others’ into its orbit. Joseph S. Nye, Jr., The Paradox of American Power: Why the World’s Only Superpower Can’t Go It Alone (New York: Oxford University Press, 2002).

[19] Robert Jervis, The Meaning of the Nuclear Revolution: Statecraft and the Prospect of Armageddon (Ithaca: Cornell University Press, 1989).

[20] Brooks and Wohlforth come to the same conclusion but for different reasons. They argue that the insurmountable U.S. lead in military power, economic strength, and technological leadership have, in effect, erased balance of power dynamics from international politics. The difference between their argument and Monteiro’s is that he believes nuclear weapons have canceled out the effect of balance of power dynamics.

[21] In other words, in a nuclear unipolar world, Mutually Assured Destruction (MAD) ensures the survival of both the unipole, and of the other major powers have nuclear deterrent capabilities.

[22] Here, Monteiro echoes Robert Gilpin’s argument that a great power will only challenge the prevailing international order when it believes the costs of doing so are outweighed by the likely benefits. Robert Gilpin, War and Change in International Politics (Cambridge: Cambridge University Press, 1981).

[23] Monteiro asserts that by eliminating the causes of competition among them, nuclear weapons transform the nature of relations among the nuclear states by making it possible for them to engage in the kind of cooperative relations posited by liberal IR theorists. “The fact that most of the great powers have nuclear weapons changes the nature of the threats posed by concentrated power (U.S. hegemony) in two ways. First, because states such as China and Russia have established a nuclear deterrent, they do not need to worry about war and domination by the leading state. American power is rendered more tolerable because in the age of nuclear deterrence, American military power cannot now be used for conquest against other great powers. Deterrence replaces alliance counterbalancing. Second, nuclear weapons also make it harder for these great powers to overturn the existing international order. The status quo international order led by the United States is rendered less easily replaced. War-driven change is removed as a historical process.” G. John Ikenberry, Liberal Leviathan: The Origins, Crisis, and Transformation of the American World Order (Princeton: Princeton University Press, 2011), 130.

[24] Monteiro defines offensive dominance as a strategy by the unipole to increase its preponderant position in the international system (6). He also says “that when implemented in regions inhabited by major powers that enjoy growing economic capabilities, offensive dominance would prompt them to balance against the unipole in an attempt to guarantee their long-term survival through continued economic growth” (6).

[25] As examples of the kinds of economic policies that the unipole must avoid if it adopts a defensive dominance strategy, Monteiro lists the following: “disrupting or limiting the flows of trade, investment, and raw materials” (100-101).

[26] It is not clear why Monteiro thinks the U.S. can practice defensive accommodation in key geopolitically important regions. The U.S. is already the dominant power in both East Asia and Europe. This would seem to rule out Monteiro’s prescribed policy of a U.S. policy of defensive accommodation in those two regions. Indeed, U.S. dominance in those regions puts America at odds with the major powers – China and Russia, respectively – located in those regions. Moscow and Beijing seek to displace the U.S. as the dominant power in those regions. For the causal logic of why great powers seek to dominate their own regions, see John J. Mearsheimer, The Tragedy of Great Power Politics (New York: W. W. Norton, 2001).

[27] Waltz, Theory of International Politics, 126.

[28] On the importance of status in international politics, see T. V. Paul, Deborah Welch Larson, and William C. Wohlforth, eds., Status in World Politics (Cambridge: Cambridge University Press, 2014).

[29] Michelle Murray, “Identity, Insecurity, and Great Power Politics: The Tragedy of German Naval Ambition before the First World War,” Security Studies, 19:4 (Fall, 2010), 660.

[30] Murray, “Identity, Insecurity, and Great Power Politics,” 665.

[31] Annika Mombauer, The Origins of the First World War: Controversies and Consensus (London: Longman, 2002), 6.

[32] Quoted in James Joll and Gordon Martell, The Origins of the First World War (New York: Pearson Longman, 2007, 3rd ed.), 148. Similarly, Margaret MacMillan observes that “The term [weltpolitik, or world policy] reflected the widespread notion among patriotic Germans that the country’s remarkable economic progress, the rapid spread of German trade and investment around the world, and Germany’s advances in such areas as science ought to be matched by an increase in its standing in the world. Other nations must recognize Germany’s achievements and its changed position.” Margaret MacMillan, The War that Ended Peace: The Road to 1914 (New York: Random House, 2013), 87-88.

[33] Quoted in Joll and Martell, The Origins of the First World War, 150.

[34] See Randall L. Schweller, “Realism and the Present Great Power System: Growth and Positional Conflict over Scarce Resources,” in Unipolar Politics: Realism and State Strategies after the Cold War, ed. Ethan B. Kapstein and Michael Mastanduno, eds., (New York: Columbia University Press, 1999), 54-56.

[35] Gilpin, “War and Change,” 14, 30, 42, 46, 48.

[36] Robert S. McNamara, “The Military Role of Nuclear Weapons: Perceptions and Misperceptions,” Foreign Affairs 62:1 (Fall 1983), 79. Also, see McGeorge Bundy, Danger and Survival: Choices about the Bomb in the First Fifty Years (New York: Random House, 1988).

[37] Henry Kissinger, Nuclear Weapons and Foreign Policy (New York: Harper, 1957). See also Robert Osgood, Limited War: The Challenge to American Strategy (Chicago: Chicago University Press, 1957).

[38] Robert Gilpin, U.S. Power and the Multinational Corporation: The Political Economy of Foreign Direct Investment (New York: Basic Books, 1975), 103-04. For a similar picture of the United States’ economic, military and financial dominance at the end of World War II, see Paul Kennedy, The Rise and Fall of the Great Powers: Economic Change and Military Conflict from 1500 to 2000 (New York: Random House, 1987), 357-361.

[39] Notwithstanding the successful Soviet test of an atomic bomb in 1949, the U.S. continued to possess nuclear superiority and unmatched power projection capabilities into the mid-1960s, when the outcome of the Cuban Missile crisis caused the Soviet Union to embark on a major buildup of both its strategic nuclear forces, and its overseas power projection capabilities.

[40] Mearsheimer, Tragedy of Great Power Politics, 133.

[41] See, Sumit Ganguly and S. Paul Kapur. India, Pakistan, and the bomb: debating nuclear stability in South Asia (New York: Columbia University Press, 2010); Sumit Ganguly, Indo-Pakistani Nuclear Issues and the Stability-Instability Paradox (London: Taylor and Francis, 1995); Sumit Ganguly, “Nuclear Stability in South Asia,” International Security 33:2 (Fall, 2008), 45-70; S. Paul Kapur, “India and Pakistan’s Unstable Peace: Why Nuclear South Asia is Not like Cold War Europe,” International Security, 30:2 (Fall 2005), 127-152; Sumit Ganguly, “Indo-Pakistani Nuclear Issues and the Stability/Instability Paradox,” Studies in Conflict & Terrorism 18:4 (April, 1995), 325-34.

[42] The January 2015 border clashes in Kashmir between India and Pakistan underscores the volatility of their relationship. See Amy Kazmin, “India-Pakistan Clashes Force Thousands to Flee Kashmir,” Financial Times, January 6, 2015 http://www.ft.com/intl/cms/s/0/076c95e6-958a-11e4-b3a6-00144feabdc0.html?siteedition=intl#axzz3OGwoUkWP.

[43] Glenn Snyder, “The Balance of Power and the Balance of Terror,” in The Balance of Power, ed. Paul Seabury (San Francisco: Chandler, 1965).

[44] The unipole almost certainly would have to organize a coalition of other economically important states to implement successfully a constriction strategy against a major power. But we have plenty of experience from attempts to impose sanctions and embargoes, that it is hard to hold such coalitions together over time. A good current example is the sanctions the U.S. and the European Union have imposed on Russia for its actions in Ukraine. Imposed in the summer of 2014, it already is apparent that “sanctions fatigue” is widespread in Europe. In early January 2015, French President Francois Hollande, called for the sanctions against Russia to be lifted. See, Andrew E. Kramer, “French Leader Urges End to Sanctions Against Russia Over Ukraine,” New York Times, January 5, 2015, and Alex Barker and Peter Spiegel, “Push to Extend Russia Sanctions Reveals EU Rift,” Financial Times, March 16, 2015.

[45] Unipoles – and hegemons – are not status quo powers. On the contrary, they are constantly seeking to expand. On this point, see Christopher Layne, “The ‘Poster Child for Offensive Realism’: America as a Global Hegemon,” Security Studies 12:2 (Winter, 2002/2003), 120-164.

[46] Gilpin, War and Change, 33-34. As Gilpin writes, prestige is closely related to credibility, and it “is achieved primarily through successful use of power, and especially through victory in war. The most prestigious members of the international system are those states that have most recently used military force or economic power successfully and have thereby imposed their will on others.”

[47] Thomas C. Schelling, Arms and Influence (New Haven: Yale University Press, 1966), 124.

[48] Quoted in Ann Scott Tyson, “U.S. Gaining World’s Respect from Wars, Rumsfeld Asserts,” Washington Post, March 11, 2005, A4. It is worth noting that the discussion about preventive war and preemption in the George W. Bush administration’s 2002 National Security Strategy of the United States of America was not limited to dealing with terrorists or ‘rogue states’ (or, as Monteiro calls them, recalcitrant minor powers).

[49] Jack Levy, War and the Modern Great Power System (Lexington: University Press of Kentucky, 1983).

[50] Another interesting question raised by Monteiro definition of great power status concerns the 1945-1949 period. He argues that the world was bipolar during those years (47). But there is a far stronger argument that 1945-1949 was the United States’ first “unipolar moment.” As Robert Gilpin observed, “In terms of absolute power, the United States, in 1945, greatly surpassed the rest of the world. In addition to her vast industrial capacity, the U.S. virtually monopolized or controlled the three sources of power in the modern world: nuclear weapons, monetary reserves, and petroleum. She alone had the atomic bomb and the knowledge to produce what at the time was called the absolute weapon. American factories produced over 50 percent of the world’s output, and America held approximately 50 percent of the world’s monetary reserves.” Robert Gilpin, U.S. Power and the Multinational Corporation: The Political Economy of Foreign Direct Investment (New York: Basic Books, 1975), 103-04. For a similar picture of the United States’ economic, military and financial dominance at the end of World War II, see Kennedy, The Rise and Fall of the Great Powers, 357-361.

[51] Here, Monteiro builds on Michael Beckley’s argument. See, Michael Beckley, “China’s Century? Why America’s Edge Will Endure,” International Security, 36:3 (Winter, 2011/2012), 41-78. Beckley notwithstanding, almost all scholars of great-power rise believe that aggregate – not per capita – GDP is the correct metric to use in evaluating states’ relative power. For an incisive critique of Beckley’s argument, see Joshua R. Itzkowitz Shifrinson, “Correspondence: Debating China’s Rise,” International Security 37:3 (Winter, 2012/2013), 172-181.

[52] Keith Fray, “China’s Great Leap Forward: Overtaking the U.S. as World’s Biggest Economy,” Financial Times, October 8, 2014 http://blogs.ft.com/ftdata/2014/10/08/chinas-leap-forward-overtaking-the-us-as-worlds-biggest-economy/#.

[53] Fareed Zakaria, From Wealth to Power: The Unusual Origins of America’s World Role (Princeton: Princeton University Press, 1998).

[54] Mearsheimer, The Tragedy of Great Power Politics.

[55] In U.S. policy circles, the consensus view is that China’s bid for regional dominance is a threat to the United States’ power preponderance. For a forceful statement of this position, see Aaron Friedburg, A Contest for Supremacy: China, America, and the Struggle for Mastery in Asia (New York: W.W. Norton, 2011).

[56] Zakaria, From Wealth to Power.

[57] Thus, when the Cold War ended, “Beijing began to worry about the ways the United States, as the world’s sole surviving superpower, might challenge China’s vital interests. But in a unipolar world there were no peer competitors of the United States to whom China could turn as allies. Consequently, while Beijing’s concerns about coping with unfettered American power grew, forging a counter-hegemonic united front [was not] a viable option.” Avery Goldstein, Rising to the Challenge: China’s Grand Strategy and International Security (Stanford: Stanford University Press, 2005), 22.

[58] Goldstein, Rising to the Challenge, 24.

[59] On “peaceful rise” see, Zheng Bijian “China’s ‘Peaceful Rise’ to Great Power Status,” Foreign Affairs 48:5 (September/October 2005), 18-24. For attribution of this maxim to Deng Xiaoping, see Aaron L. Friedberg, “The Sources of Chinese Conduct: Explaining Beijing’s Assertiveness,” Washington Quarterly, 37:4 (Winter, 2015), 147 n. 2.

[60] For discussion, see Goldstein, 35.

[61] Thus, “Deng foresaw a shift to a focus on the tasks of modernization that would provide the essential foundation for realizing the century-old nationalist goal of making China a rich, powerful, and respected member of the community of modern states.” Ibid., 25.

[62] Monteiro writes: “Taking stock we have two rational possibilities for the unipole’s grand strategy: either disengaged or defensive accommodation, other strategies are suboptimal by comparison” (215-216). On offshore balancing, see Layne, The Peace of Illusions; Mearsheimer, Tragedy of Great Power Politics; Christopher Layne, “From Preponderance to Offshore Balancing.” On restraint, see Posen, Restraint.

[63] For the argument that the U.S. is a big-time beneficiary of an open international economic system, see Carla Norrlof, America’s Global Advantage: U.S. Hegemony and International Cooperation (Cambridge: Cambridge University Press, 2010). As Monteiro puts it: “Power preponderance allows the unipole to shape the international economic environment, creating global conditions conducive to its economic growth. Although a return to bipolarity or multipolarity would not necessarily put an end to such conditions, the presence of other great powers with a global power-projection capability would place the maintenance of an international environment propitious to the former unipole’s economic growth at risk. Specifically, the rise of peer-competitors might dictate the reemergence of exclusive economic spheres of influence, closing off some markets to the erstwhile unipole and thus undermining its potential for growth. This means that unipolarity may grant an important economic dividend to the preponderant power. To the extent that it does, this will reinforce the limited security benefits that result from the possession of unparalleled military capabilities” (75-76).

[64] See David Calleo, Follies of Power: America’s Unipolar Fantasy (Cambridge: Cambridge University Press, 2010). While it is true, as Monteiro points out, that defense spending is well below Cold War levels – now at about 5% of US GDP – this does not tell the full story. Two other takes on defense spending show that it is more burdensome that Monteiro admits. First, according the Congressional Budget Office, defense spending now constitutes a greater share of discretionary federal spending than non-defense discretionary spending (which includes the seed corn of future economic growth – education, infrastructure, research and development). Also, the U.S. share of global defense spending is disproportionately high – even as the U.S. share of global GDP has shrunk. For example, in 1980 the U.S. commanded 25 % of world GDP and accounted for about 22% of world defense spending. In comparison, in 2010, the U.S. share of global GDP is about 18%. However the U.S. share of world defense spending is a shade above 40%.

[65] William C. Wohlforth, “The Stability of a Unipolar World,” International Security 24, no. 1 (1999): 5-41; Stephen G. Brooks and William C. Wohlforth, “American Primacy in Perspective,” Foreign Affairs 81, no. 4 (2002); William C. Wohlforth, “U.S. Strategy in a Unipolar World,” in America Unrivaled: The Future of the Balance of Power, ed. G. John Ikenberry (Ithaca: Cornell University Press, 2002); Stephen G. Brooks and William C. Wohlforth, World out of Balance: International Relations and the Challenge of American Primacy, (Princeton: Princeton University Press, 2008).

[66] Kenneth N. Waltz, Theory of International Politics, (Reading, Mass.: Addison-Wesley 1979).

[67] See, for example, Waltz, Theory of International Politics, 121-122; Colin Elman, “Horses for Courses: Why Not Neorealist Theories of Foreign Policy?,” Security Studies 6, no. 1 (1996): 7-53; Kenneth N. Waltz, “International Politics Is Not Foreign Policy,” Security Studies 6, no. 1 (1996): 54-57; Colin Elman, “Cause, Effect, and Consistency: A Response to Kenneth Waltz,” Security Studies 6, no. 1 (1996): 58-61.

[68] Kenneth N. Waltz, “Structural Realism after the Cold War,” International Security 25, no. 1 (2000): 5-41; Christopher J. Fettweis, “Evaluating IR’s Crystal Balls: How Predictions of the Future Have Withstood Fourteen Years of Unipolarity,” International Studies Review 6, no. 1 (2004): 79-104; Christopher Layne, “From Preponderance to Offshore Balancing: America’s Future Grand Strategy,” International Security 22, no. 1 (1997): 86-124; Christopher Layne, “The Unipolar Illusion Revisited: The Coming End of the United States’ Unipolar Moment,” International Security 31, no. 2 (2006): 7-41; Christopher Layne and Bradley A. Thayer, American Empire: A Debate, (New York: Routledge, 2007).

[69] See Robert A. Pape, “Soft Balancing against the United States,” International Security 30, no. 1 (2005): 7-45; T. V. Paul, “Soft Balancing in the Age of U.S. Primacy,” International Security 30, no. 1 (2005): 46-71; T. V. Paul, “The Enduring Exioms of Balance of Power Theory and Their Comtemporary Relevance,” in Balance of Power Revisited : Theory and Practice in the Twenty-First Century, ed. T. V. Paul, James J. Wirtz, and Michel Fortmann (Standord, Calif.: Stanford University Press, 2004), 1-28; Judith Kelley, “Strategic Non-Cooperation as Soft Balancing: Why Iraq Was Not Just About Iraq,” International Politics 42, no. 2 (2005): 153-174. For critiques of soft balancing see Stephen G. Brooks and William C. Wohlforth, “Hard Times for Soft Balancing,” International Security 30, no. 1 (2005): 72-108; Brooks and Wohlforth, World out of Balance: International Relations and the Challenge of American Primacy, chapter 3.

[70] On the distinction between theories of balancing and theories of systemic balances-of-power see Daniel H. Nexon, “The Balance of Power in the Balance,” World Politics 61, no. 2 (2009): 330-359.

[71] Brooks and Wohlforth, World out of Balance: International Relations and the Challenge of American Primacy, 38-40.

[72] Monteiro’s preconditions for grand strategy of disengagement seem more restrictive than other proposed grand strategic alternatives like offshore balancing or restraint. See Christopher Layne, The Peace of Illusions: American Grand Strategy from 1940 to the Present, (Ithaca: Cornell University Press, 2006); Barry Posen, Restraint : A New Foundation for U.S. Grand Strategy, (Ithaca: Cornell University Press, 2014); John J. Mearsheimer, The Tragedy of Great Power Politics, Updated edition. ed., (New York: W.W. Norton & Company, 2014).

[73] See Robert Jervis, Why Intelligence Fails : Lessons from the Iranian Revolution and the Iraq War, (Ithaca: Cornell University Press, 2010).

[74] Thomas L. Friedman and Patrick E. Tyler, “From the First, U.S. Resolve to Fight,” The New York Times, 2 March 1991.

[75] See William C. Wohlforth, “The Stability of a Unipolar World,” International Security, Vol. 24, No. 1 (1999): 5-41.

[76] See Kenneth N. Waltz, “The Spread of Nuclear Weapons: More May Better,” Adelphi Papers, Number 171 (London: International Institute for Strategic Studies, 1981); Robert Jervis, The Meaning of the Nuclear Revolution: Statecraft and the Prospect of Armageddon (Ithaca, NY: Cornell University Press, 1989); Robert Jervis, “International Primacy: Is the Game Worth the Candle?” International Security, Vol. 17, No. 4 (1993): 52-67; Campbell Craig, “American Power Preponderance and the Nuclear Revolution,” Review of International Studies, Vol. 35 (2009): 27-44; Daniel Deudney, “Unipolarity and Nuclear Weapons,” in International Relations Theory and the Consequences of Unipolarity, G. John Ikenberry, Michael Mastanduno, and William C. Wohlforth, editors (Cambridge: Cambridge University Press, 2011): 282-316.

[77] See Christopher Layne, “The Unipolar Illusion: Why New Great Powers Will Rise,” International Security, Vol. 17, No. 4 (1993): 5-51; Christopher Layne, “From Preponderance to Offshore Balancing: America’s Future Grand Strategy,” International Security, Vol. 22, No. 1 (1997): 86-124; Christopher Layne, “The Unipolar Illusion Revisited: The Coming End of the United States’s ‘Unipolar Moment’,” International Security, Vol. 31, No. 2 (2006): 7-41; Christopher Layne, “The Waning of U.S. Hegemony – Myth or Reality?” International Security, Vol. 34, No. 1 (2009): 147-172; Christopher Layne, “The Unipolar Exit and the End of the Pax Americana,” Cambridge Review of International Affairs, Vol. 24, No. 2 (2011): 149-164; Christopher Layne, “This Time Its Real: The End of Unipolarity and the Pax Americana,” International Studies Quarterly, Vol. 56, No. 1 (2012): 202-212.

[78] I bracket the question of whether China is indeed engaged in a bid for hegemony in East Asia and grant the point for the sake of argument. Layne writes that “China is engaged an impressive military buildup.” No doubt. Yet, much of this buildup aims at denying U.S. forces their current ability to operate with relative freedom even in close proximity to China. Parity between Chinese and U.S capabilities even in the region is way off.

[79] See David Holloway, Stalin and the Bomb: The Soviet Union and Atomic Energy, 1939-1956 (New Haven: Yale University Press, 1994), 231; Michael Gordin, Red Cloud at Dawn: Truman, Stalin, and the End of the Atomic Monopoly (New York: Farrar, Straus, and Giroux, 2009), 26-27.

[80] Quoted in David Alan Rosenberg, “American Atomic Strategy and the Hydrogen Bomb Decision,” The Journal of American History, Vol. 66, No. 1 (1979), 73.

[81] See Avner Cohen, Israel and the Bomb (New York: Columbia University Press, 1998), 55.

[82] Kenneth N. Waltz, Theory of International Politics (Reading: Addison-Wesley, 1979), 126.

[83] Layne then goes on to provide examples of past behavior that supposedly shows states risking their survival in order to pursue other goals. All his examples are from well before the onset of the nuclear age. Since in Theory of Unipolar Politics I argue that only the nuclear revolution increased the costs of war to the point where conventional competition on secondary issues risked (escalation and therefore) state survival, all these examples are irrelevant.

[84] John J. Mearsheimer, The Tragedy of Great Power Politics (New York: W.W. Norton, 2001), 31.

[85] See: Robert Jervis, “Cooperation under the Security Dilemma,” World Politics, Vol. 30, No. 2 (1978): 167-214; Charles L. Glaser, “The Security Dilemma Revisited,” World Politics, Vol. 50, No. 1 (1997): 171-201; Andrew Kydd, Trust and Mistrust in International Relations (Princeton, NJ: Princeton University Press, 2005).

[86] See: Waltz, “The Spread of Nuclear Weapons;” Jervis, The Meaning of the Nuclear Revolution.

[87] For some, the Kargil War is evidence that the so-called “stability-instability paradox” is operative between nuclear powers. See: Peter R. Lavoy, ed., Asymmetric Warfare in South Asia: The Causes and Consequences of the Kargil Conflict (Cambridge: Cambridge University Press, 2008).

[88] See footnote 4 for Layne’s germane texts.

[89] Layne also argues that “[i]n an economically interdependent world, it is improbable that even a unipole could credibly threaten the survival of a major power through a policy of economic containment.” I agree that containment is difficult to implement, particularly so in an interdependent world. This is an empirical question, however, and so I opted for including in my theory all of the possible strategies a unipole might implement, regardless of what is feasible today.

[90] See Alexandre Debs and Nuno P. Monteiro, “Known Unknowns: Power Shifts, Uncertainty, and War,” International Organization, Vol. 68, No. 1 (2014): 1-31.

[91] See: Wohlforth, “The Stability of a Unipolar World;” William C. Wohlforth and Stephen G. Brooks, World Out of Balance: International Relations Theory and the Challenge of American Primacy (Princeton, NJ: Princeton University Press, 2008); William C. Wohlforth, Stephen G. Brooks, and G. John Ikenberry, “Don’t Come Home, America: The Case Against Retrenchment,” International Security, Vol. 37, No. 3 (2012/13): 7-51.

[92] William C. Wohlforth, “How Not to Evaluate Theories,” International Studies Quarterly, Vol. 56, No. 1 (2012): 219-222, here quoted at 219.

[93] Beckley also questions my claim that “China’s assertive actions in Asia … can be dismissed as regional issues that do not affect the durability of unipolarity,” because “Asia accounts for 60 percent of the world’s population, 20 percent of global GDP, and 25 percent of world defense spending.” This largely depends on one’s definition of unipolarity, which I have discussed at length above. Here, let me just note that if one defines it the way I do in the book, which is compatible with the intuitive sense the term has been used since the end of the Cold War as signaling the preponderance of U.S. military power, then competition for regional hegemony in East Asia does not put an end to unipolarity. Is it an issue for Washington’s ability to achieve all of its policy preferences? Sure; but it does not affect the United States’ unique ability to project power beyond its own region.

[94] See: James D. Fearon, “Rationalist Explanations for War,” International Organization, Vol. 49, No. 3 (1995): 379-414; Robert Powell, “War as a Commitment Problem,” International Organization, Vol. 60, No. 1 (2006): 169-203.

[95] This argument is fully developed in Debs and Monteiro, “Known Unknowns: Power Shifts, Uncertainty, and War.”

[96] For a fully developed theory of nuclear proliferation consistent with these insights, see: Nuno P. Monteiro and Alexandre Debs, “The Strategic Logic of Nuclear Proliferation,” International Security, Vol. 39, No. 2 (2014): 7-51; Alexandre Debs and Nuno P. Monteiro, Nuclear Politics: The Strategic Logic of Proliferation (Cambridge: Cambridge University Press, forthcoming).

[97] See: Todd S. Sechser, “Goliath’s Curse: Coercive Threats and Asymmetric Power,” International Organization, Vol. 64, No. 4 (2010): 627-660.

[98] See Layne, “The Unipolar Illusion.”

[99] See Bear Braumoeller, “Is War Disappearing?” paper presented at the APSA 2013 Annual Meeting.

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