Research

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.  

Dissertation
  • 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.   Bombardment wars occur when the states only inflict costs on their opponent through air or artillery bombardment, 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. 

    Finally, bombardment wars must end with the revelation of private information, as the combatants cannot achieve their aims militarily.  However, revealing this information is difficult, as individual engagements reveal very little information.  Precipitating events may thus be necessary to prompt the end of bombardment wars.  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.  


Publications

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 2017, ISSS-ISAC 2017, MPSA 2017, Four Corners Conflict Network 2017;  Awarded CU Graduates in Political Science Paper Prize)

  • Previous research (Fearon, 1995; Powell, 2006) has suggested that power shifts can cause commitment problems leading to war.  Power shifts  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.  
  • Paper Draft
  • Appendices
"Rationalism, Social Constructivism, and Coercion."  (Presented at ISA 2018, Four Corners Conflict Network 2018, ISSS-IS 2018, MPSA 2019 ISA-West 2019)
  • Coercion, where one actor threatens to impose costs to get a second actor to do or refrain from doing something, is a central component of international relations.  Nuclear threats, coercive bombing, economic sanctions, and trade disputes all represent coercive attempts.  On face value, terrorism and guerrilla warfare would also appear to represent coercion, although they may have other purposes.  A long line of research has examined coercion, especially regarding how punishment threats can be used to deter adversaries. 

    However, by reexamining a basic model of coercion, I show that this research has missed a couple key elements in understanding coercion.  In this model, the target of coercion proposes some division of a disputed good.  Since punishment actions by definition can only impose costs, this division is automatically implemented.  The sender of the coercive threat then has the option of punishing the target, which is assumed to impose costs on both parties. 

    This model reveals three interesting aspects of coercion.  First, there is actually no fundamental difference between deterrence and compellence, as they are represented by the same basic model and there are numerous situations that are ambiguous.  However, the distinction can still be meaningful by influencing the actors’ beliefs about whether coercion will be successful.  Second, rationalist factors are sometimes sufficient to explain failed coercion, but are never sufficient to explain successful coercion.  There is always an equilibrium where the target makes no concessions, and the sender does not punish.  This may coexist with equilibria where the target does make concessions.  Thus, explaining successful coercion requires looking at socially constructed intersubjective beliefs to determine which equilibrium actually occurs – coercion will work if both sides believe it will work and fail if both sides believe it will fail.  Finally, the most likely explanations for observed punishment actions, such as implemented sanctions or coercive bombing, are different depending on the equilibrium played.  As determining the equilibrium often requires reference to socially constructed beliefs, explaining punishment actions also often requires reference to socially constructed beliefs.  

"The Bargaining Model and Alternative Explanations for War"  (Presented at ISSS-IS 2019)

  • Previous research (Fearon, 1995; Powell, 2006) has suggested that power shifts can cause commitment problems leading to war.  Power shifts  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.  

"Is War Intensity Declining? Revisiting the decline of war hypothesis"  (With Christina Boyes, Presented at ISA-West 2019, ISSS-IS 2019)

  • While a consensus is emerging that the intensity of war is declining, a few authors are more skeptical. The proportion of battle deaths relative to the world population, arguably the most relevant measure of war violence, does appear lower than in the past.  However, the only rigorous study of battle deaths relative to population (Lacina, Gleditsch, and Russett 2006) covers too short a period to draw robust conclusions about war trends.  Some studies have questioned the whether this apparent trend could be due to chance or other factors, but do not address battle deaths in relation to world population (e.g. Clauset 2017, Fazal 2014). We reanalyze the decline of war hypothesis to address methodological and temporal issues found in the existing research.  To gain a long enough time-series, we use the Correlates of War data, manually incorporating missing battle death data.  We correct for some of the methodological weaknesses in existing research by logging the battle death data to account for the skewed nature of war and address autocorrelation.  Our analysis suggests there is no clear evidence for the decline of war hypothesis, refuting the emerging consensus.