ISSF Review Essay on Logics of War: Explanations for Limited and Unlimited Conflicts

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H-Diplo | ISSF Partnership

A production of H-Diplo with the journals Security Studies, International Security, Journal of Strategic Studies, and the International Studies Association's Security Studies Section (ISSS).


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H-Diplo | ISSF Review Essay of Alex Weisiger.  Logics of War:  Explanations for Limited and Unlimited Conflicts.  Ithaca:  Cornell University Press, 2013.  ISBN:  978-0-8014-5186-7 (hardcover, $45.00).

Published by H-Diplo/ISSF on 10 December 2014


Essay by Robert Trager, University of California, Los Angeles

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.

Weisiger argues that when one of two types of commitment problem is present in international affairs, wars will be particularly destructive. The first sort of commitment problem results from shifting power: a rising state may not be able to commit to restraint once it is more powerful and a declining state may therefore choose a preventive attack. Weisiger calls this a “situational” commitment problem (4).  Such wars may end in quick and decisive victories, but there is nothing in the logic of a war animated by this dynamic that leads the war to be short or limits the war’s destructiveness.  In contrast, Weisiger argues that wars animated by other logics, in particular informational mechanisms and domestic political considerations, are naturally limited.  The conduct of a war is expected to clarify the true capabilities and resolve of opponents, leading such wars to end.  Similarly, a highly destructive war is unlikely to be in the domestic political interests of the leader who starts it.  Thus, commitment problem wars are special.  In these wars, the animating logic does not limit the degree of violence and, since states are fighting to affect the power trajectories of nations over the long-term, the declining power must make substantial demands and both sides have incentive to fight harder than in other wars.

The book points to a second sort of commitment problem, referred to by the author as “dispositional” (4).  Here, a leader is unable to commit to peaceful behavior not because of his rising power, but because of the perceptions of other states about the leader’s aggressive intentions.  One interesting aspect of the book is the argument that these two sorts of commitment problems share common features.  Dispositional commitment problem wars are also unusually destructive because only a major demand - regime change - will suffice to alter a perceived aggressive disposition.

Weisiger begins his analysis of the theoretical claims with statistical evidence.  He examines the determinants of the duration of a war, the number of battle deaths, the money spent, and the nature of the war’s termination.  To address the latter, Weisiger collected the first large-scale data on whether wars ended in conquest or settlement.  To analyze the situational commitment problem mechanism, Weisiger uses past shifts in relative power as a proxy for expected future changes.  He shows, as expected, that larger pre-war shifts in relative capabilities are correlated with the length, destructiveness, and cost of wars.  These are probably among the most important of his statistical results.  The discussion of the effects of war intensity, which are conditional on the type of war being fought, on the length of the war is also nuanced and of great interest.

In the subsequent chapters, Weisiger sets up each case as a series of puzzles framed by past scholarly understandings of the conflicts he examines. In examining the extraordinary war that Paraguay fought against its two larger neighbors, Brazil and Argentina, from 1864 to 1870, Weisiger notes that it was, “at a per capita level, quite possibly the deadliest conflict of the past two centuries.... For outsiders, the sketch of the war makes the Paraguayan president - Francisco Solano López - appear frankly insane.... Such a man seems well outside the ken of rationalist theories of war.” (86)  But Weisiger’s aim is precisely to show that this apparent outlier can be understood in rationalist terms and that López had “clear and reasonable justifications for engaging in the war that he undertook.” (86)  Similarly, the following chapter seeks to explain “history’s ultimate outlier” (105), Nazi dictator Adolph Hitler, in rationalist terms.  The reader’s attention is thus riveted by each case from the first introductory sentences.

The cases convincingly argue for the importance of commitment problem logics driving both the onset and the conduct of the wars examined. López and Hitler, for instance, both saw a window of opportunity to reverse a perceived relative decline.  Both were willing to take extraordinary risks as a result and this, along with the reactions of their adversaries, had a great deal to do with the destructiveness of the ensuing wars.

The ambition of this book is large: to explain a large part of the variation in destructiveness of conflicts and, in the cases, the onset of wars as well.  So it is no surprise that the book will not settle all of the questions it addresses.  Weisiger notes that “just about every systemic war in the modern state system has been attributed to one side’s belief that time favored its opponents.” (16) But this also suggests that commitment logics are often present and raises the issue of whether the case analysis emphasizes these in instances of long or intense wars and underplays them in less destructive conflicts.  Window-of-opportunity rhetoric may be used to justify the timing of a strike even if it is not the central animating cause of the conflict.

The analysis takes a narrow of view of what constitutes an informational explanation for conflict, defining this largely in terms of over-optimism.  Thus, the informational logic is more Geoffrey Blainey (war due to over-optimism about prospects in battle) than James Fearon (war due to the difficulty of signaling willingness to fight), and there is little discussion of the diversity of this literature.  In some of Weisiger’s cases, the attempt to assign a primary animating cause to each conflict sometimes seems a stretch.  For instance, Weisiger argues that informational explanations have at most a minor role to play in understanding World War II, but then argues that, “theory predicts that once a feared decline has occurred and the opponent is in a position to impose today the concessions that were expected down the line, there is no reason to continue to fight.” (119)  Since this seems to rule out the commitment problem as an explanation for continuing the war, why did Hitler continue to fight?  ”Down to the final days, the Germans could hope that the opposing coalition might splinter and the Western powers, whose concerns about the Soviet Union were well known, might come to Germany’s aid. This hope provided reason not to seek terms with Stalin.” (119)  This certainly appears to be an informational explanation for the continuation of the war.  The fact that multiple logics are present in single cases is not surprising and does not contradict the core of the book’s argument, however.

Other aspects of the argument that will be the subject of continuing discussion are apparent in the World War II case.  There was a large shift in relative power in the years before the war as a result of German rearmament.  In the statistical analysis, therefore, this would appear as a case of a situational commitment problem leading to preventive war on the part of the Western powers.  But the shift in power was in large part the result of specific decisions of the German leadership taken with the expectation of conflict in the future.  Thus, the statistical relationship between past changes in the balance of power and the destructiveness of a future war may derive from the expectations and intentions of leaders who choose to arm.  If this is so, then understanding the causes of the war seems to require understanding what caused these leaders to make choices that other similarly placed leaders would not have made.  This shifts the emphasis in an account of causality of the war’s onset and conduct away from an inherent commitment problem and towards an investigation of what generated the specific expansionist ideologies of the time.  This also points to a disjuncture between the statistical and case analyses because the variables employed in the statistical work will have capabilities shifting in Germany’s favor, but in his analysis of the case, Weisiger shows that German ideology led to a belief in German decline, which was the root of German aggression.

Weisiger frames the Allied response to German aggression as a dispositional commitment problem: Germany was unable to signal to adversaries that its aims were limited.  The argument is convincing, but raises the question of whether such cases should be thought of exclusively in terms of commitment problem, rather than informational, logics.  In Weisiger’s account, Germany was unable to convince its adversaries.  Perhaps a costly signal was necessary? Perhaps only certain sorts of cheap talk signaling could have been effective?  Relatedly, there are ways to question, on rationalist terms, whether wars animated by informational logics must be limited.

In this excellent book, therefore, there is much for graduate students and the best undergraduates to contemplate and discuss.  The book’s uses of theory, and qualitative and quantitative empirics are nuanced.  Weisiger brings a sophisticated understanding of the history of international relations theory to more recent debates and marries this to a careful analysis of cases, some well-known and others fascinating and understudied.  Realism, Liberalism, and Constructivism are each associated with decades of empirical analysis; with this book, rationalist theory begins to catch up.


Robert F. Trager is an Associate Professor in the political science department at the University of California, Los Angeles.  He is currently at work on a project on the sources of state preference formation and in particular on the role of fairness considerations in decision-making.  His work has appeared in International Security, the American Political Science Review, the American Journal of Political Science, International Organization, and elsewhere.


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