Roundtable 11-1 on The Evolution of the South Korea-United States Alliance57 min read

No president has cast as much uncertainty over American alliances as Donald Trump. Despite the assiduous damage control of his rotating secretaries of State and Defense and national security advisors, comments from the chief executive matter; uncertainty has increased. Moreover, the unexpected willingness of the president to undertake direct, high-level contacts with North Korean leader Kim Jong-un are both promising and unsettling. Do these contacts augur peace on the peninsula? Or are they but another example of the long-standing North Korean effort to drive wedges between the alliance partners? And looming still larger over these questions is the role that China’s rise might have in determining the alliance’s future. Will it, for example, strengthen as China’s capabilities increase and become more threatening? Or will the desire to accommodate Beijing pull South Korea away from the United States?

H-Diplo | ISSF Roundtable XI-1

Uk Heo and Terence Roehrig.  The Evolution of the South Korea-United States Alliance.
Cambridge: Cambridge University Press, 2018.  ISBN:  9781107507135 (paperback, $29.99).

16 September 2019 |
Editors: Thomas Maddux and Diane Labrosse | Production Editor: George Fujii

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Introduction by Stephan Haggard, University of California, San Diego

No president has cast as much uncertainty over American alliances as Donald Trump. Despite the assiduous damage control of his rotating secretaries of State and Defense and national security advisors, comments from the chief executive matter; uncertainty has increased. Moreover, the unexpected willingness of the president to undertake direct, high-level contacts with North Korean leader Kim Jong-un are both promising and unsettling. Do these contacts augur peace on the peninsula? Or are they but another example of the long-standing North Korean effort to drive wedges between the alliance partners? And looming still larger over these questions is the role that China’s rise might have in determining the alliance’s future. Will it, for example, strengthen as China’s capabilities increase and become more threatening? Or will the desire to accommodate Beijing pull South Korea away from the United States?

The timing of Uk Heo and Terence Roehrig’s The Evolution of the South Korea-United States Alliance could therefore not be better. The following reviews by Brad Glosserman, David Kang, Mason Richey, and Andrew Yeo summarize the book’s contribution, dissect and debate its contents, and require little by way of introductory comment.

One overarching issue that bears mentioning at the outset, however, is how alliances are conceived. At the spare end, the alliance is nothing more than the obligations outlined in the pithy Mutual Defense Treaty of 1953. Viewed through this lens, the overarching analytic questions have to do with the credibility of commitments: how the U.S. would respond to a crisis and whether the extended deterrent is credible. Other issues are ultimately peripheral.

The analytic questions surrounding the credibility of alliance commitments have been worked and reworked, and are notoriously difficult to demonstrate. On the one hand, Heo and Roehrig acknowledge the somewhat counterintuitive fact that the Korean peninsula—despite threats of ‘fire and fury’—has been surprisingly stable.

On the other hand, their more expansive view of the alliance—and the correct one in my view—underlines a broader, and ever-shifting, set of objectives. The ‘never again’ focus of the Mutual Defense Treaty gave way in the 1950s and 1960s to efforts to promote economic development, and in the 1970s to President Jimmy Carter’s unwelcome—at least to South Korean leader Park Chung Hee—introduction of political and human rights issues. From 2002, the alliance was increasingly shaped by the ups and downs of the nuclear crisis, which is now nearing 20 years in duration.

What Heo and Roehrig do not address directly is that this more expansive conception of an alliance effectively adopts a liberal institutionalist approach. Alliances are not just about the formal treaty commitments, but the increasingly robust institutional infrastructure, both formal and informal, that instantiate the relationship. This infrastructure ranges from an increasingly dense network of alliance institutions—centered on summits, ministerial meetings, and the Security Consultative Meetings and their committees—to the economic commitments contained in the recently-renegotiated United States-Korea free trade agreement (KORUS) and the various collaborative projects that typically arise around presidential summits.

But even these more formal structures would not fully capture the scope of the alliance under this more expansive conception. The formal institutions and rules are not ends in themselves but means for unleashing a variety of other economic and even social ties. To cite one example: shouldn’t we see the large numbers of Americans in Seoul on any given day, or the tens of thousands of Korean students in the United States, as effective components of the alliance relationship? Think, for example, of the significance of the former as a source of credibility.

An explicit focus on alliances as complex institutions would provide a grounding for the book’s generally optimistic conclusions: that the alliance has not only largely achieved its objectives but may even be under less stress than is often thought. Theoretically, an institutionalist view focuses our attention to a greater extent on path dependence, and as a result views political perturbations, even as significant as Trump’s, as less disruptive than they appear. Heo and Roehrig do not explicitly cast their book in these terms, but as the reviewers suggest, grappling with the most fundamental question—what an alliance ultimately is—would sharpen the ongoing controversy of where the alliance is going.


Uk Heo is University Distinguished Professor of Political Science at the University of Wisconsin-Milwaukee and Editor of Asian Survey. He has authored or coauthored five books and more than 60 journal articles.

Terence Roehrig is Professor of National Security Affairs and Director of the Asia-Pacific Studies Group at the Naval War College. He has written on Korean and East Asian Politics and Security including Japan, South Korea, and the United States Nuclear Umbrella with Columbia University Press.

Stephan Haggard is the Krause Distinguished Professor at the School of Global Policy and Strategy at the University of California San Diego. He received his Ph.D. at the University of California Berkeley. His publications on international political economy include Pathways from the Periphery: The Newly Industrializing Countries in the International System (Cornell University Press, 1990); The Political Economy of the Asian Financial Crisis (Institute for International Economics, 2000); and Developmental States (Cambridge University Press, 2018). His work with Robert Kaufman on democratization, inequality and social policy includes The Political Economy of Democratic Transitions (Princeton University Press, 1995); Democracy, Development and Welfare States: Latin America, East Asia, Eastern Europe (Princeton University Press, 2008); and Dictators and Democrats: Masses, Elites and Regime Change (Princeton, 2016). His work on North Korea with Marcus Noland includes Famine in North Korea (Columbia University Press, 2007), Witness to Transformation: Refugee Insights into North Korea (Peterson Institute for International Economics, 2011) and Hard Target: Sanctions, Inducements and the Case of North Korea (Stanford University Press, 2017). He is currently editing a volume on the long history of international relations in Asia with David Kang

Brad Glosserman is deputy director of and visiting professor at the Center for Rule Making Strategies, Tama University and a senior advisor (nonresident) at Pacific Forum, a Honolulu-based think tank. He is the author of Peak Japan: The End of Great Ambitions (Georgetown University Press, 2019) and co-author with Scott Snyder of The Japan-ROK Identity Clash: East Asian Security and the United States (Columbia University Press, 2015).

David C. Kang is Maria Crutcher Professor of International Relations at the University of Southern California, with appointments in both the School of International Relations and the Marshall School of Business. Kang is also director of the USC Korean Studies Institute. Kang’s latest book is American Grand Strategy and East Asian Security in the 21st Century (Cambridge University Press, 2017). He has authored four other scholarly books, and has published articles in journals such as International Organization, International Studies Quarterly, Journal of Conflict Resolution, and International Security. A regular consultant for U.S. government agencies and the military, Kang has also written opinion pieces in the New York Times, the Financial Times, the Washington Post, and the Los Angeles Times, and appears regularly in media such as CNN, PBC, the BBC, and NPR. A former Fulbright Scholar, Kang received an A.B. with honors from Stanford University and his Ph.D. from Berkeley.

Mason Richey is associate professor of international politics at Hankuk University of Foreign Studies (Seoul, South Korea). Dr. Richey has also held positions as a POSCO Visiting Research Fellow at the East-West Center (Honolulu, HI) and a DAAD Scholar at the University of Potsdam. His research focuses on US and European foreign and security policy as applied to the Asia-Pacific. Recent scholarly articles have appeared (inter alia) in Pacific Review, Asian Security, Global Governance, and Foreign Policy Analysis. Shorter analyses and opinion pieces have been published in War on the Rocks, 38North, the National Interest, the Lowy Interpreter, Le Monde, the Sueddeutsche Zeitung, and Forbes, among other venues.

Andrew Yeo is Associate Professor of Politics and Director of Asian Studies at The Catholic University of America in Washington DC. His two most recent books are Asia’s Regional Architecture: Alliances and Institutions in the Pacific Century (Stanford University Press 2019), and with Danielle Chubb, North Korean Human Rights: Activists and Networks (Cambridge University Press 2018). His research and teaching interests include international relations theory, East Asian regionalism, Asian security, overseas basing strategy, the formation of beliefs and worldviews, civil society, Korean politics, and North Korea.


Review by Brad Glosserman, Center for Rule-making Strategies,
Tama University

The United States-South Korea alliance is under unprecedented strain. The mixing of U.S. President Donald Trump, who is suspicious of if not hostile to alliances, North Korean leader Kim Jong-un, a shrewd and seductive diplomat, and Republic of Korea (ROK) President Moon Jae-in, a progressive whose priorities remain unclear, has yielded a toxic combination for this bilateral security partnership that has endured for over half a century. At a time of potentially wrenching change, an accurate understanding of the U.S.-ROK alliance is needed now more than ever. The Evolution of the South Korea-United States Alliance is a valuable primer on that relationship, but it is at the same time a barebones account of the alliance and the changes it has experienced.

Their narrative is straightforward and conventional. Chapter 1 lays out the theoretical basis for the alliance, using alliance theory, deterrence theory and development power theory. The authors note that the role of the smaller partner is not well studied and they seek to fill that gap. Chapter 2 looks at the formative years of the U.S.-ROK bilateral relationship and the early years of the alliance. Chapter 3 explores the impact of South Korea’s transition to democracy and its impact on the alliance. Chapter 4 then examines the evolution of threat perceptions in the U.S. and the ROK, focusing on whether they align and tensions that emerged when they diverge. Chapter 5 looks at the economic dimension of the alliance – a challenge for purists who would argue that such issues are, strictly speaking, outside the purview of a security alliance. Chapter 6 turns to the nuts and bolts of the alliance – roles, missions and structures. Particular attention is given to the transfer of Operational Control (OpCon) of the alliance, which remains in U.S. hands despite an agreement by the two governments to put Seoul in charge by 2012. The authors end with a concluding analysis, predictions for the future of the alliance, as well as claims about the contributions made by the study to alliance theory.

Their argument, in brief, is that an alliance formed by two countries with vastly different capabilities has evolved into a far more equitable partnership, despite the continuing asymmetries that mark place of the two countries in the world. Their path to that conclusion is well documented, although the authors have a tendency to cite their own work, something that is understandable, but, to me at least, a bit awkward.

Uk Heo and Terence Roehrig seek “to explain how endogenous growth and political development make for the transformation of an asymmetric alliance to a cooperative partnership” (11). They tell a compelling story. It can be faulted—not fatally, however—on two counts. First, it reflects the view of alliance traditionalists.[1] While I largely agree with their strategic logic and its underpinnings, they overlook parts of alliance history that tarnish the largely uncritical narrative they tell. For example, while they detail the many provocations that North Korea has visited upon the South that justify identifying Pyongyang as an enemy, there is no mention of southern provocations against the North. Similarly, the authors fault the George W. Bush administration for criticizing Pyongyang’s violations of the spirit of the Agreed Framework; in fact, the U.S. suspended oil shipments that were a central part of that deal, and the construction of lightwater reactors, another integral component of the agreement, was well behind schedule. There is ample blame to go around for the collapse of the Agreed Framework.

Second, Heo and Roehrig’s account, while complete, lacks nuance. An understanding of the issues that bedevil the U.S.-ROK relationship today demands attention to details. Consider, for example the distinction between the concepts ‘asymmetrical alliance’ and ‘cooperative partnership.’ While the relationship has evolved, the alliance remains asymmetrical; the U.S. retains far greater capabilities and responsibilities (a function of its global interests and commitments) than does its ally. The two countries are working to forge a more ‘cooperative partnership,’ in which there is a reassigning of responsibilities on the Peninsula, along with more burden sharing and more coordination among the two governments. Trump’s demand that Seoul assume more of the cost of the alliance (which, to my mind, is wrong on fundamental levels) focuses on those enduring asymmetries.

Nuance is particularly important when analyzing anti-Americanism. It is true that the U.S. presence in South Korea has been overwhelming and that Washington enabled conservative governments that did not hesitate to repress progressive forces (109-110). But progressives had reason to be aggrieved even without overt or conscious action by the U.S. The central role of the U.S. in ROK politics and security has meant that ties to the U.S., or even the ability to speak English, have provided a means of advancement that was often denied to the left.

Similarly, progressive forces in South Korea could have a view of North Korea that differs from that of the U.S. (or South Korean conservatives) without necessarily being sympathizers or juche (the official ideology of North Korea) dupes. Reformers in the South have sometimes downplayed the threat posed by Pyongyang because they believed that a focus on that threat prevented governments in Seoul from implementing a domestic agenda that would transform the economy. The national security state helps block large-scale economic reform.

Presumably, the book’s focus on the U.S.-ROK alliance explains the failure to mention Japan’s role in the rejuvenation of the South Korean economy. There is no mention of the importance of the hundreds of millions of dollars provided by Japan when it normalized relations with the ROK in 1965. Those funds (and the Japanese development model that the government of Park Chung Hee adopted) laid the foundation for the ROK’s economic success. That bilateral focus also accounts for the absence of any discussion of Japan-ROK relations, a topic that may seem tangential but is of increasing importance as the U.S. and the ROK respond to an evolving North Korean threat. U.S. bases in Japan are critical to the defense of South Korea and security planners in all three countries recognize the need to integrate the two alliances as seamlessly as possible.

Another curious absence is that of China, which was instrumental in turning the tide of the Korean War when UN forces took the offensive, and continued to offer Pyongyang post-armistice protection in an alliance that was famously touted to be “as close as lips and teeth.”[2] In recent years, China has assumed an outsize role in South Korea’s economy, giving Beijing the means to punish Seoul for decisions it does not like. China has also tried to convince successive ROK governments that the road to Pyongyang runs through Beijing (within limits; China makes no claim that it can actually deliver North Korea when it comes to crucial decisions). Both arguments aim to encourage greater deference in Seoul to Chinese prerogatives, even—or especially—if this drives a wedge between Seoul and Washington. There is concern in the U.S. (and among ROK conservatives) that China is subverting the ROK commitment to the alliance.

In recent years, however, Chinese heavy-handedness has prompted a backlash in South Korea. There has been a hardening of views toward China, and the prospect of a more aggressive approach toward China by the alliance, which was once anathema, is now being discussed. This has potentially sweeping implications for the U.S.-ROK relationship. U.S. forces on the peninsula take on a whole new meaning if they can be deployed elsewhere in the region, a flexibility that has previously been denied to U.S. strategic planners.

These are quibbles, however. The Evolution of the South Korea-United States Alliance is a solid assessment of that security partnership.



Review by David C. Kang, University of Southern California

Uk Heo and Terence Roehrig have written an important book about the United States-South Korea (ROK) alliance. In a sweeping exploration of the many dimensions of this relationship, Heo and Roehrig provide a valuable and detailed account of this alliance. In particular, Heo and Roehrig examine the domestic politics as well as the important and often overlooked economic dimension of the alliance (Chapter 5), and provide a nuanced and careful history of the alliance from before its inception to the present (Chapter 2). This is in addition to the authors’ masterful research on the more usual military and security dimensions of the alliance, which they cover with deep competence. This book is central for anyone hoping to understand the U.S.-ROK alliance is today and the dynamics between the two countries. Heo and Roehrig show how the alliance has evolved over time as the ROK has grown richer, stronger, and more democratic, and the ways in which these domestic changes within Korea have precipitated evolution of the alliance and adjustments by both sides.

This comprehensive study has much to commend it, and it sits firmly within the scholarly literature on the U.S.-ROK alliance. The two books most closely associated with The Evolution of the South Korea-United States Alliance would be Victor Cha’s Powerplay, and Michael Green’s By More than Providence.[3] Cha argues that the U.S. created the alliances it did in East Asia in order to control truculent and unpredictable allies, such as South Korea’s Syngman Rhee or China’s Chiang Kai-shek. Green argues that the U.S. has historically consistently acted to prevent the rise of a hegemon in East Asia, and that the U.S. intervention in Korea in 1950 was a central element in that vein. In this way, Heo and Roehrig’s work builds upon and supplements these perspectives.

Heo and Roehrig show that although the alliance was originally intended for national security, as the ROK recovered from the Korean War, grew rich, and democratized, the alliance has changed along with the ROK. The nature of the alliance changed as well: from a very clear initial patron-client relationship, where a clearly subordinate South Korea basically followed the U.S. lead, the alliance has evolved into a much more equal relationship, with the ROK taking on much more of the financial burden and the initiative for adjusting the alliance. In 1994, for example, Seoul received operational control of its military during peacetime, and even transfer of wartime operational control of the joint forces has been actively considered. Heo and Roehrig argue that the alliance is firmly supported by both sides, and that despite inevitable tensions at times, the ‘Joint Vision’ that the two sides signed a decade ago remains vital as a means for adjusting and evolving the alliance itself. They argue that “as the North Korean nuclear problem has intensified, support for the alliance has increased,” (238), pointing out that a clear majority of South Koreans support the alliance and the stationing of U.S. troops in their country (160).

In this short review I wish only to express a few thoughts, none of which fundamentally challenges the argument in the book. But these points might point us in the direction of more research or further attention, because the alliance is continuing to evolve in response to changes in the region, within Korea itself, and perhaps just as consequentially, in the U.S. as well. My main reaction to this wonderful book was that Heo and Roehrig tend to take for granted a relatively widely held perspective: that South Korea wants the alliance more than the United States.

In fact, Heo and Roehrig are firmly within the traditional international relations literature on alliances, which tends to assume that when a smaller country faces a powerful adversary, the smaller state is likely to pursue an alliance with a powerful patron to counterbalance that threat (see, for example, page 14).[4] It is often assumed that the demand for alliance by the smaller power exceeds the supply of alliance from the larger power, and that the small power fears abandonment by the patron, while that the patron fears entrapment by the small power.

However, it is just as likely that the large power, not the smaller power, seeks allies. Large powers often have ambitions, and often pursue smaller powers in order to extend their own prestige and influence or to create and sustain expansive or even hegemonic ambitions.

This assumption can drive empirical analysis in consequential ways. As mentioned, in East Asia, for example, it is widely argued that small countries such as Korea actively seek the protection of the United States. This also assumes that the United States is reluctant and hesitant to commit too strongly to South Korea, for fear of being entrapped into a conflict it does not wish, or being taken advantage of as the smaller ally gets a free ride.

At this point in time, it is particularly important to ask whether President Donald Trump is the exception or the trend. Trump’s willingness to question the utility of alliances has provoked a storm of concern in both Seoul and Washington about the alliance in particular, and about the U.S. hegemony more generally. Trump’s behavior actually fits conventional theoretical expectations about alliances, but the president is also firmly opposed by many influential U.S. foreign policy analysts. The mainstream criticisms from Washington about declining U.S. leadership, hegemony, and influence certainly provide probative evidence that in this case, at least, scholars and officials in the powerful patron state care at least as much about maintaining the alliance as does the small ally.[5] U.S. critics from both left and right have worried that Trump’s foreign policy could be undermining American interests and influence.[6] Critics worry that even slight reductions in the military preparedness of U.S.-ROK forces could be dangerous, and caution against any rethinking of the alliance or the burden sharing.[7]

However, on policy, Trump agrees with the mainstream Washington consensus and sees China and North Korea as imminent threats, and expects the ROK to support the U.S. strategy. There is strong evidence that in this case it is the eager patron and the reluctant protégé, not the other way around.

The central question about what are the key national security threats for each country has important implications for the alliance. Indeed, the ROK and U.S. have diverged for some time in their enduring conceptions of the relative threat from China and the threat from North Korea. In both cases, it is the distance patron (the U.S.) that appears more worried about the threat than the small, proximate protégé (the ROK). It often appears that the U.S. is chasing South Korea, not the other way around. On this matter there are important implications for both the alliance and larger perspectives on East Asian security. As Heo and Roehrig point out, both progressive and conservative South Korean leaders—and a majority of the population—deeply value the U.S.-ROK alliance. But at the same time, those leaders view the nature of the North Korean threat in a manner that differs from the views of the Trump administration; South Korea fairly clearly views China as less threatening than does the mainstream U.S. foreign policymaking establishment. This has implications for the alliance that have not yet manifested themselves. In the short run, Trump is disrupting the alliance in a range of ways, from his skepticism about alliances in general to his willingness to reconsider the foundations of the alliance, such as the burden sharing agreement that Heo and Roehrig discuss (245-252) or withdrawal of U.S. forces from the peninsula.  But this should not cloud the fact that Washington and Seoul have enduring, and different, threat perceptions.

Indeed, it is probably safe to argue that American leaders and policymakers tend to be more skeptical of China’s rise than do those in South Korea. This has already caused friction, as Heo and Roehrig note, regarding the deployment of a U.S. radar battery (THAAD) to South Korea (231-234). Yet the issue is larger than a missile battery; Koreans in general are less skeptical of China than most Americans want; and they are more skeptical about Japan than most Americans believe is warranted. Thus, Korea is often considered a less reliable ally than Japan, which views China with suspicion and clearly cleaves to the U.S. as its main partner. This is perhaps best evidenced by opinion polls in South Korea that consistently see Japan as a greater threat than China. For example, even after the China-South Korea dispute over the THAAD batteries, a South Korean Asan Institute poll from July 2018 showed that China’s favorability rating (4.16 out of 10) in June 2018 was significantly higher than that of Japan (3.55).[8] These consistent opinion poll results are almost always dismissed in the U.S. as either wrong or in need of correction—but perhaps they should be taken as an enduring South Korean conception of the world.

At the same time, the South Korean public has always had a greater propensity to support engagement with North Korea. Although the political pendulum swings left and right, the baseline appetite for engagement in South Korea is greater than it is among the U.S. establishment. In the context of the past year, this means that South Korean president Moon Jae-in found himself in the awkward position of acting as a go-between between Supreme Leader Kim Jong-un of North Korea and President Donald Trump. Although this may be a passing phase, the real question is whether South Korea and the U.S. will continue to see eye-to-eye on the two biggest threats—North Korea and China. In both cases, Trump’s policies have deviated from the mainstream Washington consensus for postwar U.S. hegemony, and he is more willing to confront China and (at best temporarily) considered engaging directly with North Korea. Trump is also skeptical of alliances and wants South Korea to pay more for the costs of the alliance. Indeed, if there is one minor criticism I would make of The Evolution of the South Korea-United States Alliance, it is that the authors do not devote much attention to South Korea-China or South Korea-Japan relations. Most of the book’s foreign policy focus is on North Korea. But as the region has changed over time, so too have relations, and the U.S.-ROK alliance itself.

How all this plays out is anyone’s guess, but the alliance is undergoing changes and stress in ways unthinkable before.  Heo and Roehrig have provided an important and timely addition to the literature on alliances in general and about U.S.-Korea relations in particular. It is especially pertinent as the alliance undergoes enormous stresses and adjustments that have been caused by the unlikely diplomatic events of the past two years.



Review by Mason Richey, Hankuk University of Foreign Studies

In 2017, the Korean peninsula was a powder keg dangerously close to explosion, a consequence of nuclear and missile tests ordered by North Korean leader Kim Jong-un, as well as U.S. president Donald Trump’s saber-rattling response of ‘fire and fury’ and ‘maximum pressure.’ Fortunately, a series of diplomatic maneuvers have led to a sustained détente, including South Korea-North Korea summits on inter-Korean reconciliation and three Trump-Kim summits on denuclearization.

The latter have been rightly derided as spectacle rather than real summitry. They were woefully under-prepared by working-level officials, while Trump demonstrated both over-reliance on personal chemistry with Kim and an inability to learn his brief. One of the sideshows of the Washington-Pyongyang nuclear diplomacy circus has been speculation about Trump’s willingness to sacrifice the U.S.-South Korea alliance as part of a grand bargain for North Korean denuclearization. Although the likelihood of drastic alliance diminishment was always low, the attention paid to its possibility was not misplaced, given Trump’s well-known antipathy toward alliances in general and frequent disparaging remarks about the alliance with South Korea in particular. Seoul drew ire for inadequate burden-sharing, both for routine elements of the military alliance and, in particular, U.S.-South Korea military exercises that are the heart of joint readiness. Prior to the Singapore meeting Trump mused about his desire to eliminate U.S. troop presence on the peninsula, and during his post-summit press conference he unilaterally announced suspension of major U.S.-South Korea joint military exercises.

Regardless of what one thinks of the present wisdom of a U.S.-South Korea military alliance, Uk Heo’s and Terence Roehrig’s The Evolution of the South Korea-United States Alliance shows that it is resilient. Trump notwithstanding, if the history the authors provide is any guide, Washington and Seoul will remain joined at the hip on security and defense matters for the foreseeable future. This conclusion is implicated in Heo’s and Roehrig’s core narrative: the alliance was born in a Cold War crucible of shared security threats stemming from expansionist Communism, has been transformed into a comprehensive relationship incorporating shared values, and survives in strong form despite emerging threats to the prevailing Asia-Pacific security architecture and the emergence of North Korea as a nuclear power capable of striking the U.S. mainland with nuclear-armed ballistic missiles. The alliance’s evolution has included radical changes to the reality and perception of security threats to both partners; the end of the Cold War and its concomitant bipolar international system; a complete makeover of South Korea’s political identity and governmental system from authoritarianism to democracy; South Korea’s development into a wealthy country with global economic and trade capacity capable of competing with the United States; the inevitable frictions between local populations and foreign-garrisoned troops; and a few moments of serious divergence between Seoul and Washington regarding the strategic value of maintaining the alliance. The central mission remains deterrence of North Korean aggression against South Korea, but the task of supporting regional stability has grown in importance, as has the necessity that South Korea contribute to the alliance in a more reciprocal and balanced fashion.

Given the current critical juncture of diplomacy on the Korean peninsula, The Evolution of the South Korea-United States Alliance is very timely context. Its task of providing a comprehensive survey of the U.S.-South Korea alliance not only fills a gap in the literature,[9] but allows the reader to understand the current, healthy state of the alliance as a function of path dependence, alliance management efforts, and an underlying strategic logic. The text is filled with historical narrative supported by facts and statistical data, and it is easy to see that the book will be an authoritative reference for scholars of the U.S.-South Korea alliance, Northeast Asian security and economics, U.S. regional foreign policy, Korean history, and Korean studies.

Apart from an initial chapter on alliance theory, the book is structured as a thematic and chronological overview. Following an introductory chapter, chapter 1 covers theoretical perspectives on alliance formation and maintenance, with heavy emphasis on realist approaches privileging alliance partners’ shared threat perceptions and interest in deterrence. These are certainly worthy (indeed standard) factors for understanding the creation and endurance of alliances, although the limited space dedicated to theory results in a certain mechanical, perfunctory approach to theoretical perspectives. One can also critique the exclusion of constructivist, institutionalist, or bargaining theory[10] perspectives—those lacunae indicate a constricted theoretical Weltanschauung. The flip side, however, is that the clear theoretical focus on threat perception and deterrence as driving forces in alliances generally means that the theoretical argument is easily applicable to the specific U.S.-South Korea case, especially at the end of World War II and into the Cold War period.

Chapters 2 and 3 bore down into the history of the U.S.-South Korea alliance, starting from the early period of Washington-Seoul relations in the nineteenth century, through the Korean colonial period under Japanese rule (until 1945), to the division of the peninsula during the Cold War, and, last, the democratic and economic transition of South Korea into a full-fledged U.S. partner in terms of both capabilities and values. In chapter 2 the authors recount tales of early Korea-U.S. contact (often at gunpoint), the subtleties of early U.S.-Korea treaty language, and how that language led to Korean disappointment at the lack of U.S. involvement in defending Korea from Japanese colonial predation. Chapter 2 also does a fine job covering the lead-up to, and significance of, the Korean War (1950-1953), and how that traumatic conflict led to the modern U.S.-South Korea mutual defense treaty and military alliance. The chapter does not cover the war itself in great detail, a task that has been done by countless other texts.[11] Instead it weaves a story of U.S. distraction, confusion, miscalculation, and, finally, resolve in handling the division of the peninsula, the lead-up to war, and the defense of the South from North Korean attack. The highlights are well known, but told efficiently: the U.S. under President Harry Truman did not give much thought to the Korean peninsula at the end of World War II and scrambled to settle on the 38th parallel as dividing line; the U.S. feared South Korean president Rhee Syngman was as likely to entangle the U.S. in a conflict with the North as the North was to attack the South; the U.S. misunderstood the power dynamics between Pyongyang and Moscow; and the war’s outbreak caught the U.S. by surprise. U.S. leaders learned from these mistakes, however, and, as the remainder of chapter 2 elucidates, established a military alliance with South Korea based on four elements: a formal security treaty, U.S. economic and military assistance, U.S. combat troop deployment in South Korea, and the provision of extended nuclear deterrence (including the stationing of nuclear weapons on South Korean soil).

Chapter 3 features the authors’ description of South Korea’s long, non-linear march to democratization. The historical details are interesting: the way feckless U.S. President Jimmy Carter failed to advocate effectively for South Korean democracy (as he also failed in his attempt to withdraw U.S. troops); how South Korean democracy activists were inspired by the case of Filipino democratization; and how the U.S. hardly covered itself in glory regarding democracy promotion in the 1980s, in part as a result of seeing the outcome of the 1979 Iranian revolution. The murky, conflicted U.S. response to the 1983 Gwangju massacre, in which South Korea’s authoritarian leader Chun Doo-hwan ordered a military crackdown on protesters that killed many, has had particular repercussions for the alliance. To this day there remains a meaningful minority of South Koreans who believe that the U.S. impeded South Korean democratization. Moreover, they continue to harbor suspicions that the U.S. presence on the Korean peninsula is against South Korean interests, notably vis-à-vis the prospect of South-North unification. This profile fits a number of figures who are (or were) senior members of the current Moon Jae-in presidential administration in South Korea; their vision of the pace of inter-Korean reconciliation and economic cooperation is both out of step with Washington’s emphasis on sanctions and undergirded by a sense that the U.S. is again standing in the way of Korean political destiny. Throughout the Cold War the U.S. chose to prioritize anti-Communist stability over democratization, and, when it finally came, the U.S., in South Korea as elsewhere, had to adapt to allied populations who eventually gained the freedom to criticize, rightly or wrongly, the U.S. role in their countries. As the saying goes: sow the wind, reap the whirlwind.

Chapter 4 discusses the security motivations for the U.S.-South Korea alliance, while Chapter 5 covers the economic dimensions of Washington-Seoul relations, with much focus on how South Korea’s improving economic stature led to both complementarity and competition with the United States. Chapter 4 starts with the United States’ haphazard drawing of the 1949 ‘Acheson line,’ an Asian regional defense perimeter named after the eponymous Secretary of State, that excluded the Korean peninsula, and then goes into a recounting of the course of the Korean War, which involved a UN mandated international force defending the South, and, eventually, Chinese ‘volunteer’ troops aiding the North and helping bring the war to a painful stalemate. The legacy of the involvement of these two non-Korean participants in the Korean War casts a long shadow over the peninsula, and indeed over Northeast Asian security. The Korean War infamously ended with an armistice rather than a peace treaty, which means both China and the United Nations (UN) coalition of sending states would likely play a diplomatic role in bringing the war to a close with a proper peace treaty. Beyond the Korean War, much of chapter 4 deals with the various U.S. approaches to security provision on the Korean peninsula in the context of the evolving Cold War. This is a fascinating period in U.S.-South Korea relations, with many anecdotes worthy of Cold War thrillers: Communist infiltration into South Korea using methods ranging from tunnels to submarines; North Korean assassinations of high-ranking South Korean figures; South Korean dictator Park Chung-hee’s assassination by his own intelligence chief; Pyongyang-directed bombings of civilian airliners; and so on.

Overall the message of chapter 4 is one of increasing détente in the Cold War accompanied by shifting U.S. doctrine, force size, and force posture on the peninsula. As an increasingly wealthy South Korea became more capable of defending itself, the U.S. reduced its troop levels. Shortly after the end of the Cold War, the U.S. withdrew its nuclear weapons (although extended nuclear deterrence remained in place), but this was ironically met with North Korea’s efforts in the 1990s to create a nuclear arsenal in order to make up for an increasingly unfavorable conventional military balance. Despite North Korea’s formidable artillery and rocket emplacements along the demilitarized zone, it is currently these asymmetric threats—nuclear arms, chemical/biological weapons, and cyber attacks—that represent a significant and growing security concern on the part of the alliance.

Chapter 5, on the development of U.S.-South Korea economic relations, may not appear as sexy as the sections on guns, bombs, and spies, but it is the part of the alliance that most obviously affects the daily lives of South Korean citizens, whose country has experienced extraordinary economic growth since the 1950’s. Indeed South Korea is now one of only a few countries in the ‘30-50 club,’ states with U.S. $30,000 in GDP per capita and a population of more than 50 million. This would not have been possible without U.S. economic assistance, preferential trade ties, and, indeed, U.S. security provisions for South Korea, which was consequently able to focus on attracting foreign investment and establishing competitive industries. The obverse of this positive alliance development is that South Korea has come to represent an economic challenger to U.S. industry in several sectors, a state of affairs which naturally causes friction. Even the signing of a U.S.-Korea free-trade agreement (KORUS FTA) has not stopped this dynamic, as President Trump demanded revisions to the treaty in 2018 in an attempt to reduce the United States’ trade deficit with South Korea.

Chapter 6 looks at the highly institutionalized U.S.-South Korea military relationship, and, in particular, how it is has changed as South Korea gained the capabilities to defend itself and as the U.S. reduced its troop presence on the peninsula following the end of the Cold War. United States Forces Korea (USFK) and the Combined Forces Command (CFC) have generally seen an increase in interoperability and fighting effectiveness, as force posture and size, technology, and operational planning and training have achieved remarkable depth and flexibility to adapt to a changing security environment. A testament to this is the fact that U.S. forces stationed on the peninsula have shrunk to 28,500 and are in the process of re-locating to bases south of Seoul, as South Korea continues the trend of taking over more front-line responsibility. The capstone for this will be a full remanding of wartime operational control (over its own forces) to the South Korean military, once Seoul completes a set of operational criteria and technical and capability achievements. Of course not all aspects are positive, as Heo and Roehrig point out, noting in particular disagreements over burden-sharing; South Korea’s difficult and controversial decision to station a U.S.-demanded Terminal High Altitude Area Defense (THAAD) battery on South Korean territory; South’s Korea’s adverse demographic development (which will have major consequences on its military size); and ongoing difficulties in adapting to North Korea’s asymmetric capabilities.

Chapter 7 offers a conclusion looking forward to the future of the U.S.-South Korea alliance. It is in this context that it makes sense to mention some of the books weaknesses. One of the primary problems is that the book is highly descriptive, offering little in original research from archives, interviews, or quantitative methods. This presents two problems. First, the book does not generalize easily to other cases, a problem worsened by the weak theory chapter at the beginning. Second, the book’s focus on descriptive narrative means it will lose value as time progresses and new facts supersede the old. Indeed, the book already suffers from lack of in-depth discussion about the ongoing diplomatic process involving the U.S., South Korea, and North Korea. There are also a few surprising omissions. There is too little about the possibility of U.S.-South Korea-Japan trilateral defense and security cooperation, which is a major desideratum of Washington yet which is frequently stonewalled by parochial concerns on the part of Seoul (and, to be fair, Tokyo). Perhaps more significantly, there is too little focus on the China factor. Certainly the primary task of the U.S.-South Korea alliance is the deterrence of North Korean aggression, but a clear, and increasingly more salient, function is the role of the U.S. military presence in South Korea as an over-the-horizon force aimed at keeping China in check. Unfortunately, the book does not adequately deal with this issue.

In the end, these criticisms are quibbles. The book is well done and those with an interest in Northeast Asia will be well served to buy it.



Review by Andrew Yeo, The Catholic University of America

The U.S.-South Korean alliance has taken a back seat to U.S.-North Korea relations this past year as U.S. President Donald Trump and North Korean leader Kim Jong-un have now engaged in two high profile summit meetings. However, in their new book, authors Uk Heo and Terence Roehrig remind readers of the central role the U.S.-South Korean alliance has played in deterring North Korea and maintaining stability on the Korean Peninsula. Recent criticism from President Trump about the cost of alliances notwithstanding, in many ways the U.S.-South Korean alliance has become routine, and for the most part, uneventful. This is in part a testament to the success of the now sixty-six year old alliance, which is anchored by the Mutual Defense Treaty signed by both countries in 1953.

Although the U.S.-South Korean alliance remains relatively stable, the alliance is anything but static. In The Evolution of the South Korea-United States Alliance, the authors are keen to demonstrate the dynamic elements of this alliance relationship. Words such as “transformation,” ‘change,” “progress,” and “growth” appear throughout the book as the authors discuss the changing nature of bilateral relations and its drivers. As the authors write, “the main objective of this book is to analyze how the South Korea-United States alliance has evolved over the past 60 years” (4). Noting the asymmetric nature of this alliance relationship, the authors give more weight to the weaker member of the alliance in explaining change. In their theoretical framework, three factors produce alliance change: 1) shifts in external threat perceptions and power configurations; 2) domestic political change, and the process of democratization, which elevates to power new elites with different perspectives about threats and the alliance; and 3) broadened national interests and increased national pride (47). Shifts in all three factors over time have resulted in the transformation of the U.S.-South Korean alliance from a patron-client relationship to a genuine strategic partnership.

The book makes for an excellent primer on the U.S.-South Korea alliance. It is both brief in its survey of the historical relationship and comprehensive in highlighting key issues of contention that are central to the alliance, including extended deterrence, threat perceptions of North Korea, operational command and control, free trade, shared values, and troop deployment. The book is ambitious in its attempt to cover the economic, security, and domestic political dimensions of the alliance in a single volume.

Following the introduction and the theoretical framing chapter, the authors briefly chronicle the early relations between the U.S. and South Korea in Chapter 2. They begin with the late nineteenth century and then walk readers through the decades of the alliance from its formal establishment in the aftermath of the Korean War up to the current decade. The chapter is succinct and useful for readers who are unfamiliar with the alliance. Unlike other historical treatments of South Korea-U.S. relations during the Cold War, the authors make a point in distinguishing between U.S. conventional and nuclear force deployments. To that end, the authors offer a useful chronological timeline of the introduction and withdrawal of U.S. tactical nuclear weapons in South Korea (76).

Domestic political change and external security motivations are really the key drivers behind the evolution of the U.S.-South Korean alliance, and particularly its transition from a Cold War to a post-Cold War security alliance. The authors devote much of Chapter 3 to a discussion of South Korea’s democratic transition and the ensuing domestic political pressure from South Koreans to push the alliance towards greater equality and sovereignty. Democratization helped better align South Korea’s political system and values towards a democratic one, generating space for the two sides to develop a deeper relationship. However, a more open political environment also paradoxically created the potential for greater friction by enabling protestors to criticize the U.S. military presence and to voice their dissent without fear of imprisonment (122).

Chapter 4 presents the security motivation for the alliance, and the military balance between the two Koreas and that of the United States Forces Korea (USFK). The authors note the large numerical advantage in numbers of the North Korean military, but are clear that the “quality of the ROK force is superior to those of North Korea” (142). Nevertheless, Heo and Roehrig believe North Korea poses a real and credible threat due to its asymmetric assets, including chemical and biological weapons, and its growing nuclear weapons capacity (143).

Some alliance observers will dispute Heo and Roehrig’s characterization of North Korean threat perceptions.[12] In contrast to some experts who see gradual reductions in North Korean threats perceptions since the Cold War (or inflation of the North Korean in recent years), the authors argue that “threat levels experienced very little change” (159) in the post-Cold War period. Moreover, North Korea’s growing nuclear weapons and ballistic missile programs means that “the original threat has remained and become more menacing for the United States, as it has always been for South Korea” (159). Heo and Roehrig’s overall premise that a common security threat will remain central to the alliance “for years to come” is a fair assessment. However, the existence of an increasingly progressive South Korean public which has been generally supportive of North Korean diplomatic engagement the past year may dispute the authors’ claims about the persistence of high levels of threat. The authors do seem to concede some ground in the book’s concluding chapter where they acknowledge the possibility of shifting security perceptions, especially among the younger generation of South Koreans (258).

Chapters 5 and 6 will be of great interest to readers who want to know how the U.S. and South Korea might navigate their bilateral relationship under the current Trump administration. Chapter 5 is devoted to economic relations between the two countries, an aspect of the alliance that is often neglected or treated as an after-thought. The chapter provides two useful reminders about economic relations and trade in the Trump era. First is the important and positive role U.S. economic aid and investment played in building up security partners. The second is that in almost every decade since the 1960s, Seoul and Washington experienced some degree of friction related to trade imbalances. The Trump administration’s assailing of South Korea and other allies on trade issues, while perhaps undiplomatic in its delivery, is not unprecedented. Although it took place before the publication of this book, the 2018 renegotiated Korea-U.S Free Trade Agreement supports the authors’ argument that alliances can weather political storms so long as a strategic rationale remains intact and alliance managers continue to work through issues through frequent dialogue.

The authors address the changing military dimensions of the alliance in Chapter 6. In a section headed “Is it Time to Remove U.S. Troops?” Heo and Roehrig address the very question President Trump has raised on several occasions in the context of improved U.S.-North Korea relations. Over the past year, questions about current U.S. troop levels, the future presence of USFK, and the transition of wartime operational control (OPCON) from the U.S. to South Korea have been contemplated by policy analysts in private and public. To the authors’ credit, they do not attempt to speculate whether or under what conditions troop withdrawals may occur. Instead, they acknowledge both the importance of the alliance to date and the need for regular dialogue, but also leave open the possibility of changing defense commitments by concluding that “change has long been a part of … South Korea –United States military relations and the evolution of this part of the alliance will continue in the years ahead” (237). The book’s concluding chapter addresses some of the specific issues of alliance contention including defense burden sharing, shifting security perceptions regarding North Korea, and South Korea’s position between U.S.-Sino competition.

The authors provide readers with an excellent understanding of the U.S.-South Korean alliance, drawing extensively on the secondary literature and some primary documents and reports from both English and Korean sources. They also provide useful statistical data on information such as the military expenditures and capabilities of North and South Korea, trade data between the two countries, South Korean defense burden share data, and an appendix with a list of North Korean incursions and provocations against South Korea between 1950 to present.

Contrary to the authors’ intent to use the alliance “as a case study to contribute to the literature on alliance theory,” (11) they do not really advance any new theoretical insights on alliance politics. This may reflect that fact that the book covers only a single alliance, even one that can be examined across six decades. Of the several books devoted solely to the U.S.-South Korea alliance, only one in the past fifteen years, Jae-Jung Suh’s Suh, Power, Interest, and Identity in Military Alliances, really manages to raise the theoretical bar on alliance politics.[13] Nevertheless, the authors still persuasively demonstrate how “endogenous growth and political development make way for the transformation of an asymmetric alliance to a cooperative partnership” (11). What the book lacks in its theoretical framing, it more than makes up for in its readability and usefulness in uncovering the history and politics of the U.S.-South Korea alliance.



Response by Uk Heo, University of Wisconsin-Milwaukee, and Terence Roehrig, Naval War College

We want to start by expressing our thanks to H-Diplo and Tom Maddux for organizing this roundtable and for Brad Glosserman, David Kang, Mason Richey, and Andrew Yeo who provided thoughtful commentary on our book. The questions and points they raise are important to ponder and consider for future study. While the reviews address several noteworthy points, we would like to focus on five in our response.

In many respects, this study is a continuation of the work we began in our previous book, South Korea’s Rise: Economic Development, Power, and Foreign Relations.[14] There we introduced a theoretical framework that describes how economic growth and political development affect a country’s foreign policies and international relations. The theoretical framework was refined and labelled “Development Power Theory” in a subsequent article.[15]  The theory posits that economic development leads to the transition to democracy, increased international trade, and foreign direct investment, which expands national interests worldwide, greater resources for achieving foreign policy objectives, including increased military spending to strengthen the armed forces, and stronger national pride, all of which influence the nation’s foreign policies.

To examine the evolution of the South Korea-United States alliance, we developed our theoretical framework by couching Development Power Theory in the context of alliance and deterrence theories since a common security threat was the main reason for the birth of the alliance. Our theory maintains that as the weaker member of an asymmetrical alliance develops its economy, two things may happen. The transition to democracy may follow, meaning power shifts in domestic politics are likely to occur based on electoral outcomes. The threat perceptions and interpretation of national interests will likely vary as different administrations along the ideological spectrum alternate in power. Second, economic achievement may enhance national pride and available resources of the weaker member of the alliance creating a stronger and more confident partner. As a result, public perception of the alliance in the weaker state may change and thus alter the nature of the relationship.

Given that the theoretical framework we employed for this book is a variant of Development Power Theory that we introduced elsewhere, we do realize that our theoretical contribution to the alliance literature with this book may be limited. That said, we still believe that the theory we introduce in this book makes important theoretical contributions to the literature in three ways. First, our theory links the literature on economic development and democratization, alliances, deterrence, and foreign policy. By doing so, we provide a big-picture look on how the national economy, domestic politics, and foreign policies are all interconnected. Second, the theory provides a useful framework to describe how endogenous factors such as economic growth and political development of the weaker member of an asymmetrical alliance modifies the nature of the existing relationship. For example, prior to significant economic development of the weaker member of the alliance, the bilateral relationship may be hierarchical with alliance decisions dictated largely by the stronger side. With the economic success of the weaker country, the relationship may become more cooperative, with decisions made through negotiations based on shared interests so that the United States’ desire to keep the alliance is as high as South Korea. Third, although our theory was applied to a single case, the South Korea-United States alliance, the theory can be applied to any asymmetrical alliance relationship that experiences the economic growth and political development of the weaker member. In other words, our theory, just like any other social science theory, does have generalizability although further applications are needed for empirical support.

Second, South Korea’s economic growth and political development have led to changes in the alliance, evolving from its beginning as a patron-client relationship to more of a partnership that is multi-faceted with important political and economic dimensions as well as its initial and primary focus on security. We argue that while the relationship has evolved to more of a strategic partnership, not that many of the basics of an asymmetric alliance have gone away. Chapter 1 that lays out the theoretical foundations, and we note that our study “will also help explain how and why asymmetrical alliances change, a phenomenon that is applicable to other enduring asymmetrical alliances.” (18) The power differentials between the United States and South Korea in both economic and military spheres are obvious and unlikely to change. However, the dynamics of this “enduring asymmetrical alliance” have evolved as South Korea has increased its power in political, economic, and military terms, while producing a broader set of national interests along with the confidence to be an international player. These changes have also manifested themselves within the alliance though the fundamental relationship remains asymmetric.

Third, all the reviewers point out a lack of attention to the role played by China and Japan among the exogenous factors examined in our study. This is a fair critique. The book includes some discussion of China and Japan at various points and concludes with an assessment of China’s impact on the alliance in the years ahead. Yet, in retrospect the book would have benefitted from a more detailed treatment of the role played by China and Japan for several reasons. China’s rise is and will continue to be a critical issue in alliance relations. Beijing’s economic pull for South Korea will remain and brush up against the U.S. role as South Korea’s chief security partner.

In addition, while the U.S. alliances with South Korea and Japan are separate, bilateral relationships, they have always been interconnected. Should hostilities ever break out in Korea, basing arrangements in Japan facilitated through the United Nations Command (UNC)-Rear will be crucial for the flow of U.S. forces and those of other UNC states to the war effort. The credibility of the U.S. commitment for these two allies is linked; what Washington does with one ally is followed closely by the other. Finally, the United States. has long sought to increase trilateral cooperation between these alliance partners in a host of ways including ballistic missile defense, joint exercises, and high-level trilateral meetings between defense and foreign policy officials. Yet given the continued frictions between Seoul and Tokyo over issues related to their history and the Dokdo/Takeshima territorial dispute along with different threat assessments of China, increased cooperation has been, and likely will remain, difficult. All of these factors play an important role in the South Korea-United States alliance.

With that said, our discussion of the South Korea-United States alliance places less emphasis on China and Japan because our theoretical framework focuses on how endogenous factors such as economic growth and political development have affected South Korea’s alliance with the United States. Thus, we chose to focus on the domestic changes of the weaker member of the alliance and its impact on the relationship with the stronger alliance member, believing that an extended discussion of China and Japan was beyond the scope of the book.

David Kang raises an important point about the motivation that underlies the alliance and how this has changed as well. He notes that our book takes for granted the typical assessment “that South Korea wants the alliance more than the United States,” placing a greater emphasis on the weaker side of the asymmetrical alliance than is warranted. In fact, Kang argues, the evidence, based on the many critics that challenge the Trump administration’s dismissal of alliances, points to the reverse with an “eager patron” and “reluctant protégé” in the current relationship.

In many respects, the roots of this assessment go back to the Cold War. When the United States came to South Korea’s defense, it was less about any assessment of the intrinsic value of the country and more about how defending Korea was crucial to U.S. interests in halting the spread of Communism. This logic also applied to the early days of the alliance; while South Korea desired U.S. protection, Washington also needed to defend South Korea to maintain regional stability and contain Communist expansion. The United States did not necessarily need South Korea but it did need to maintain the country’s presence in the U.S. camp. As time went on and South Korean power and international standing grew, the intrinsic value of South Korea increased to the United States as a political, economic, and security partner.

Yet this rise also spawned critiques of the value and costs of the alliance to U.S. interests. Thus, some began to call for the withdrawal of U.S. forces from the peninsula in the late 1970s, in part to ensure the United States would not become involved in another war in Asia, and in part based on the fact that South Korea was becoming more than capable of defending itself without Washington’s help. In many respects, the criticisms of the Trump administration are echoes of these earlier concerns. Today, much of the debate on this issue revolves around Sino-U.S. rivalry in the region. For many in Washington, South Korea is a valuable asset for the United States in its competition with China, yet South Korea has already shown a reluctance to play that geopolitical game in the way Washington wishes. As Stephen Walt notes, a common perception of the underlying threat is central to the endurance of an alliance and “if the threat declines, or if it is supplanted by a greater one, then an alliance formed to counter the original threat is likely to change.”[16] Debates continue in South Korea and the United States over the implications of China’s rise and the corresponding threat perceptions. The results of these debates in the respective foreign policy communities could cause further change to the alliance.

Finally, the South Korea-United States alliance was created based on common threat perceptions. However, these assessments have changed over time for various reasons. South Korea’s economic growth allowed for increased military expenditures with South Korean forces developing into a modern and capable military that is much better equipped than their counterparts in North Korea. Threat assessments also changed with South Korea’s democratization, allowing power shifts between conservatives and progressives. While conservatives continue to view North Korea as a primary security threat, progressives perceive North Korea from a compatriotic perspective where North Korea is a poor cousin rather than a serious threat. As a result of these differing perceptions, South Koreans remain at odds over assessments of the North Korean threat. In addition, due to China’s rise and North Korea’s development of nuclear weapons and intercontinental ballistic missiles, the United States’ view of the North Korean threat is different from South Korea’s which further complicates the alliance today and into the future. Differing security perceptions between Seoul and Washington become particularly apparent when South Korea has a progressive president while the U.S. president is conservative.

An alliance that lasts over six decades will not remain static; there are likely to be changes in the power of the individual alliance members, the relationship matrix within the alliance, and the external threat environment that will all affect the overall dynamics of the alliance. This has certainly been the case for the South Korea-United States alliance. Our book seeks to develop a theory to explain how the endogenous factors impact and alter the workings of the alliance. The evolution of this relationship is an ongoing story. The alliance will continue to experience challenges and change as any long-term partnership does, but with regular and determined alliance management by both partners, the relationship will endure.



[1] See, for example, Scott Snyder, ed., The U.S.-South Korea Alliance: Meeting New Security Challenges, (Boulder: Lynn Rienner Publishers, 2012); Jonathan Pollack and YK Cha, A New Alliance for the Next Century: The Future of U.S.–Korea Security Cooperation, (Santa Monica: Rand Corporation, 1996); or Gi-Wook Shin, One Alliance, Two Lenses: U.S.-Korea Relations in a New Era, (Stanford: Stanford University Press, 2010).

[2] Graham Hutchings, Modern China: A Guide to a Century of Change (Cambridge: Harvard University Press, 2003), 252.

[3] Victor D. Cha, Powerplay: The Origins of the American Alliance System in Asia (Princeton: Princeton University Press, 2016); Michael Green, By More Than Providence: Grand Strategy and American Power in the Asia Pacific Since 1783 (New York: Columbia University Press, 2017).

[4] See, for example, Stephen Walt, “Alliance Formation and the Balance of World Power,” International Security 9:4 (Spring 1985): 3-43.

[5] See, for example, Richard Haass, “Liberal World Order, R.I.P.,” Project Syndicate (21 March 2018),

[6] Ted Barrett, “Democrats warn Trump on North Korea deal,” CNN (4 June 2018),

[7] Abraham Denmark and Lindsey Ford, “America’s Military Exercises in Korea Aren’t a Game,” Foreign Policy (21 June 2018),

[8] Asan Institute, “U.S.-North Korea Summit and South Koreans’ Perceptions of Neighboring Countries,” (6 July 2018),

[9] Selected, recent cognate works include: Scott Snyder (ed), The US-South Korea Alliance: Meeting New Security Challenges (Boulder: Lynne Rienner, 2012); Victor Cha, Powerplay: The Origins of the American Alliance System in Asia (Princeton: Princeton University Press, 2016); Terence Roehrig, Japan, South Korea, and the United States Nuclear Umbrella: Deterrence After the Cold War (New York: Columbia University Press, 2017); Scott Snyder, South Korea at the Crossroads: Autonomy and Alliance in an Era of Rival Powers (New York: Columbia University Press, 2018).

[10] Tongfi Kim, The Supply Side of Security: A Market Theory of Military Alliances (Stanford: Stanford University Press, 2016).

[11] Max Hastings, The Korean War (New York: Simon and Schuster, 1987); David Halberstam, The Coldest Winter: America and the Korean War (New York: Hachette, 2008); Bruce Cumings, The Korean War: A History (New York: Modern Library, 2010); Sheila Miyoshi Jager, Brothers at War: The Unending Conflict in Korea (New York: W.W. Norton, 2014).

[12] David C. Kang, “They Think They’re Normal: Enduring Questions and New Research on North Korea: A Review Essay,” International Security 36:3 (2012): 142-171; Doug Bandow, “The North Korean Threat: Disengage and Defuse,” Cato At Liberty (blog), 15 April 2013,

[13] Jae-Jung Suh, Power, Interest, and Identity in Military Alliances (New York: Palgrave Macmillan, 2007).

[14] Uk Heo and Terence Roehrig, South Korea’s Rise: Economic Development, Power, and Foreign Relations (Cambridge: Cambridge University Press, 2014).

[15] Uk Heo and Terence Roehrig, “Development Power Theory: The South Korean Case.” Pacific Focus 33:1 (2018): 111-140.

[16] Stephen M. Walt, “Why Alliances Endure or Collapse,” Survival 39:1 (1997), 163