In “The Demographic Transition Theory of War,” Deborah Jordan Brooks, Stephen Brooks, Brian Greenhill, and Mark Haas set out to show that the likelihood of experiencing the onset of interstate conflict shifts dramatically downward as states pass through a demographic transition. Demonstrating this trend statistically is no easy task. Interstate conflicts are rare events, which typically involve a confusing multi-state mix of actors. Yet, Brooks and her colleagues, who make some innovative methodological choices, succeed in convincingly demonstrating that this expected downward trend can be observed in at least four standard demographic measures—median age, the youth-bulge ratio, total fertility rate, and life expectancy at birth. Perhaps most interesting, for their set of interstate conflict data (1960 to 2001) the authors find that the peak probability of onset for interstate conflict is not at the earliest extremes of these variables.
The fog of war plays a prominent role in Carl von Clausewitz’s reflections on armed struggle. In Ann Hironaka’s rethinking of war, that fog becomes all consuming, obscuring the information needed to understand and prepare for battle. Victory in war is unpredictable and tantamount to random in clashes between competitors with roughly comparable power (41). Power being hard to measure, strategists can rarely know how costly a war will be. Predictions of casualties in the 1991 Gulf War, for example, were too low by an order of magnitude (10). Strategists commonly miscalculate the best strategy in a given context, for example, seeing the offense as having the advantage on the eve of World War I while expecting the defense to dominate in World War II. With profound uncertainty encumbering military analysis, defining the national security interest of the state becomes arbitrary, Hironaka argues.
Occasionally, the long timelines of academia have an upside. Matthew Baum and Philip Potter’s War and Democratic Constraint was published in 2015, and these reviews were set in motion prior to Election Day. But President Donald Trump’s surprise victory has, among other things, refocused attention on the nature—and fragility—of democratic institutions. Although Baum and Potter’s book had both scholarly and policy relevance before 8 November 2016, it has taken on new significance and urgency in the election’s aftermath.
Philip Haun’s Coercion, Survival and War: Why Weak States Resist the United States is a much-needed book. After over a decade where the struggle against terrorism dominated policy, conflicts among states—such as the tension between China and Japan over disputed islands or European and U.S. efforts to push back against Russia’s attempts to expand its sphere of influence—are now at the front and center of policymakers’ concerns and may prove the most important security issues for the Trump administration.
Haun’s work presents a general theory of coercive failure, arguing that too often coercers insist on too much—in particular demands for regime change and surrendering territory. Such demands are…
This short piece focuses on mapping and evaluating some of the expectations of International Relations (IR) theory with regard to the potential effects of Trumpism and the illiberal turn in world politics on war and peace. Obviously, there is a high degree of uncertainty here, but that does not mean that such an intellectual exercise cannot be helpful in highlighting some of the potential consequences of the major changes taking place on the important subject of war and peace. The mere fact of rising uncertainty in international politics is, by itself, going to have some significant effects, which we should try to explore.
Jonathan Caverley challenges our image of democracies – and mass publics – as being relatively averse to war. The costs of war, he correctly argues, are not distributed evenly across all citizens. Those who are taxed less heavily than others or do not serve in the military, he reasons, will be less averse to war and will support more aggressive foreign policies, favor more military spending, prefer more capitalized armies that substitute equipment and technology for individual soldiers, and fight insurgencies inefficiently. He tests this argument using public opinion surveys linking income to attitudes and case studies of the expansion of the franchise in nineteenth-century Britain and the overly capitalized wars fought by the United States in Vietnam and Israel in southern Lebanon. This is an original and insightful contribution to the literature on war and international security more generally, and is an outstanding example of how mixed-method research designs are often more persuasive than any single method design. It deserves a broad audience, especially as it appears that the United States and others will be confronted with many ‘small wars’ and insurgencies in the years ahead. If Caverley is right, we are doomed to fight these wars badly and ineffectively.
Dale Copeland’s Economic Interdependence and War is an ambitious book that should receive close attention from both international-relations theorists and diplomatic historians. The author’s main objective is to offer an alternative explanation of the relationship between commerce and international conflict, one that challenges both liberal and realist theories. In his view, liberals are correct to believe that increasing trade and investment flows can enhance the prospects for peace, but realists also have solid grounds for believing that increased economic interdependence can lead to conflict and war. It is because both theories are plausible, Copeland argues, that it is necessary to consider an additional variable that he defines as “a state’s expectations of the future trade and investment environment” (2). When states have positive expectations about the future trade and investment environment, they are unlikely to resort to war. But if a state has negative expectations about the future, it is going to be more willing to consider war as an attractive policy option. It is this argument that Copeland tests against the historical evidence of great-power conflict from 1790-1991 and also applies to the future of U.S.-Chinese relations in the twenty-first century.
The book produced by Alex Weisiger is a substantial contribution to rationalist theory in international relations. Weisiger investigates the effects of commitment problems in international bargaining on the conduct, duration, and destructiveness of wars. The book is among only a few works that closely analyze international history from the perspective of recent developments in the theory of international bargaining. Weisiger is superb at framing history as a series of mysteries, the answers to which he dramatically unravels. In addition to its contribution to research on international conflict, therefore, the book is immensely valuable as a teaching tool.
In Petro-Aggression: When Oil Causes War, Jeff Colgan provides an indispensable starting point for researchers interested in the relationship between oil and international conflict. Although the term ‘energy security’ is now ubiquitous in political speeches and the media, international relations scholars have only just begun to rediscover the topic after a thirty-year hiatus. The 1970s oil shocks prompted a wave of research in the 1970s and 1980s but did not produce systematic theories about oil and war. Emerging scholarship assesses the potential threats to energy-importing countries and examines how energy security issues shape importers’ foreign policies, including their decisions to use military force. Colgan’s book makes a unique contribution by examining a topic that has otherwise received little attention: how oil might encourage conflict initiation by “petrostates,” which he defines as countries for which oil exports comprise 10% of gross domestic product (GDP) or more (2).
The book under discussion here is The Arc of War: Origins, Escalation, and Transformation by two political scientists of international relations, each with impressive track records of work drawing on both historical detail and political science theory. It is a very ambitious book that deserves close attention by an interdisciplinary audience such as the readers of H-Diplo. The authors’ ambition may seem vaulting, and the book is susceptible to tough criticism. Yet ambition can be laudable, and they have their chance to make a spirited rebuttable defense at the end.