My research explores the why states choose to begin and end wars and other conflicts.  I work primarily within the bargaining model of war, popularized by James Fearon (1995).  Within this framework, there should always exist some negotiated settlement that states prefer to war, as fighting incurs significant costs.  Thus, war should only occur between rational states if there is uncertainty or private information such that states cannot recognize the mutually preferred settlement, or power shifts make it impossible to credibly commit to implement the settlement.  In my research, I aim to develop the bargaining model by including a more detailed account of conflict processes, particularly those related to military strategy.  

  • How do interstate wars end?  I explore this question in my dissertation by developing the bargaining model of war (e.g. Fearon (1995, Powell 2006, Wagner 2000, Filson and Werner 2002 and others) to include a more detailed account of war processes.  In particular, I examine how military strategy affects interstate bargaining and how this relates to war termination.  Several significant developments emerge from this examination.  First, it becomes apparent that there are in fact two fundamentally different bargaining situations in interstate wars.  Ground wars occur where the states attempt to take and hold territory and can achieve their objectives militarily.   Punishment wars occur when the states only inflict costs on their opponent through bombardment or guerilla attacks, and must rely on their opponent voluntarily making concessions to achieve any changes to the status quo.  Second, examining war termination relative to the military situation at the end of the war shows that standard bargaining explanations fail to adequately explain the actual end of most wars.  Wars typically end before credible commitment issues have been fully resolved.  However, most wars do not appear to involve freely negotiated settlements, as war outcomes tend not to be intermediate to the two sides’ war aims and tend not to involve one side making preemptive concessions before they have been militarily lost.  I argue that in ground wars, defensive advantages present commitment problems internal to the war, inhibiting war termination until one side has achieved their war aims.  However, once one side, and particularly the stronger, has achieved their war aims, defensive advantages actually cement a war ending settlement.  In contrast, punishment wars must end with the revelation of private information, as the combatants cannot achieve their aims militarily.  However, revealing this information, about the possibility of a ground invasion in the case of bombardment and about the possibility of eliminating guerilla forces in guerilla conflicts, can take significant time, as individual engagements reveal very little information.  I empirically test these theories with originally coded data on military campaign outcomes.  I supplement the quantitative analysis with multiple case studies, demonstrating that the hypothesized mechanism does occur.  


Beard, Steven and Josh Strayhorn.  2018.  When Will States Strike First?: Battlefield Advantages and Rationalist War.International Studies Quarterly.  62(1):  42-53. 

  • Previous research suggests that first-strike advantages can create commitment problems that lead rational leaders to opt for war, even when both sides are perfectly informed. In this article, we develop a formal model that extends upon this work. We include a more detailed account of war processes in order to determine what factors are most likely to cause first-strike advantages that lead to war. In particular, we decompose first-strike advantages into three underlying dimensions: tactical offensive advantages, mobilization advantages, and the destructiveness of an initial attack. Our model also allows states to counterattack, rather than, as typical in the literature, assume a single-stage conflict. By studying the interaction of these factors, we uncover surprising results about wars produced by first-strike advantages. First, offensive advantages can lead to war in the absence of mobilization advantages. However, they only do so when successful attacks can destroy an extremely large proportion of the enemy's military power. In contrast, mobilization advantages always increase the likelihood of war. Surprisingly, mobilization advantages are particularly likely to lead to war when combined with defensive advantages. We demonstrate that these mechanisms can explain war initiation through an examination of the 1967 and 1973 Arab-Israeli War

Working Papers

"When Do Power Shifts Cause War?"  (Presented at APSA 2018, ISSS-ISAC 2018, MPSA 2017, Four Corners Conflict Network 2017;  Awarded CU Graduates in Political Science Paper Prize)

  • Power shifts have been identified as a major cause of rational war through creating commitment problems (Fearon, 1995; Powell, 2006), and are widely used to explain both interstate and civil wars.  In this paper, I develop a formal model to reevaluate the logic of how power shifts cause war.   I relax the unrealistic assumption, included in previous models, that power shifts settle disputes permanently.  In addition, I include multiple possible causes of commitment problems in the same model.  Surprisingly, this model shows that rapid shifts in the underlying power balance can never be a proximate cause of rational war.  This model thus undermines the ``better now than later'' understanding of preventive war.  Instead, commitment problem wars are driven by disputes over indivisible sources of bargaining power, such as strategic territory, or regime type.  Among other interesting implications, a longer shadow of the future can make war more likely.  
"A Rationalist Model of Compellence."  (Presented at ISA 2018, Four Corners Conflict Network 2018)
  • Economic sanctions, coercive bombing, terrorism, and many guerilla wars represent a common bargaining situation.  In each of these cases, the target of coercion retains complete control over the conflict outcome.  The coercer cannot directly achieve their goals with the means chosen, and only the potential costs of future punishment could induce concessions.  In this paper, I examine this basic model of compellence, which reveals several interesting findings.  In any finite duration game, punishment actions are completely useless in inducing concessions as long as they are mutually costly.  In infinitely repeated versions of the game, equilibria do exist where the target does make concessions.  However, these always coexist with an equilibrium where the target makes no concessions, and no punishment is initiated.  These no concessions equilibria exist even if there is uncertainty and regardless of the relative costs of the punishment to the two parties.  I suggest that in coercion scenarios, the no-concessions equilibrium is generally more likely than the concessions equilibrium, as the target has a greater ability to adopt a policy of never making concessions.  Thus, observed sanctions, coercive bombardment and terrorism can only occur in two basic cases.  First, punishment may be an attempt to shift the equilibrium, which requires the development of a theory of equilibrium choice.  Second, they may occur for purposes other than immediately inducing concessions, such as being of symbolic value, serving as a costly signal for more direct action, or changing the opinion of publics or third parties.