Patricia L. Sullivan

War Aims and War Outcomes: Why Powerful States Lose Limited Wars

Why are states with tremendous advantages in capabilities and resources often unable to attain even limited objectives vis-à-vis much weaker adversaries? The theory I develop focuses on how the nature of a strong states war aims affects prewar uncertainty about the cost of victory. I argue that the relative magnitude of the effect of military strength and resolve on war outcomes varies with the nature of the object at stake and that strong states become more likely to underestimate the cost of victory as the impact of resolve increases relative to that of war-fighting capacity. I evaluate the empirical implications of this theory against the historical record provided by the universe of major power military interventions since World War II. The results challenge both existing theories and conventional wisdom about the impact of factors such as military strength, resolve, troop commitment levels, and war-fighting strategies on asymmetric war outcomes.

War Aims and War Outcomes

Why are states with tremendous advantages in capabilities and resources often unable to attain even limited objectives vis-à-vis much weaker adversaries? The theory I develop focuses on how the nature of a strong states war aims affects prewar uncertainty about the cost of victory. I argue that the relative magnitude of the effect of military strength and resolve on war outcomes varies with the nature of the object at stake and that strong states become more likely to underestimate the cost of victory as the impact of resolve increases relative to that of war-fighting capacity. I evaluate the empirical implications of this theory against the historical record provided by the universe of major power military interventions since World War II. The results challenge both existing theories and conventional wisdom about the impact of factors such as military strength, resolve, troop commitment levels, and war-fighting strategies on asymmetric war outcomes.

Should I Stay or Should I Go Now? Partisanship, Approval, and the Duration of Major Power Democratic Military Interventions

How does the domestic political climate within democratic states affect the duration of their foreign military engagements? To answer this question we combine a rationalist model of war termination with a theory about how partisan politics affects the policy preferences of national leaders to predict the duration of democratic military interventions. Specifically, we examine how changes in a chief executive’s public approval ratings interact with partisanship to affect decisions about the timing of conflict termination. We test our expectations on a set of 47 British, French, and American cases from a new dataset of military interventions by powerful states. Our results suggest that partisanship mediates the effect of public approval on the duration of military operations initiated by powerful democratic countries. As executive approval declines, governments on the right of the political spectrum are inclined to continue to fight, while left-leaning executives become more likely to bring the troops home.

Military Intervention by Powerful States, 1945-2003*

The Military Intervention by Powerful States (MIPS) project develops a rigorous, generalizable measure of the effectiveness of military force as a policy instrument and applies the measure to code the outcomes of all military interventions conducted by five major powers since the termination of World War II. The MIPS dataset provides detailed data on US, British, Chinese, French, and Russian uses of military force against both state and non-state targets between 1946 and 2003. In particular, this project focuses on the political objectives strong states pursue through the use of force, the human and material cost of their military operations, and measures of intervention outcomes relative to the intervening states’ objectives. The dataset also includes extensive data on factors commonly hypothesized to be associated with war outcomes, such as the nature of the target, the type of force used by the intervening state, and military aid and assistance provided to each side.

Sustaining the Fight: A Cross-Sectional Time-Series Analysis of Public Support for Ongoing Military Interventions

What determines a democratic publics willingness to tolerate the human and material costs of sustaining ongoing military operations to victory? Athough much literature has addressed the factors that affect public attitudes toward the use of military force, few studies adopt either a theoretical perspective or a research method explicitly designed to answer this question. In particular, existing research tends to focus on the costs of war fighting, while ignoring both the tangible and intangible costs of withdrawing from a foreign military engagement. I argue that many of the factors that the public uses to estimate the cost of prosecuting a war—troop strength requirements, whether or not troops are engaged in ground combat and, most importantly, casualties—are also measures of the extent of a states commitment to achieving its war aims. If the public treats the cost of the states military commitment simply as an expense , support for sustaining an operation should decrease as the cost of commitment increases. If, however, citizens have a tendency to see military commitments as investments that put the countrys reputation on the line or can only be redeemed if the state is victorious in the war, an increase in commitment could actually strengthen the publics determination to sustain the fight. Employing a cross-sectional time-series design with data from 12 U.S. and British military interventions, I explore whether the costs of continuing to prosecute a war or the costs of withdrawing have a greater effect on public willingness to sustain ongoing military operations. The results suggest that public concern about the costs of withdrawing from a conflict can be a more important determinant of willingness to persevere than sensitivity to the costs of war fighting. As a result, there is a considerable disconnect between what the public claims it would support in hypothetical scenarios and the types of military operations the public actually shows a willingness to sustain once they are underway.

Disaggregating Peace: Domestic Politics and Dispute Outcomes

Drawing on arguments about the domestic political costs of using force and the ability of states to signal resolve, we develop a selection effects-based model of militarized interstate dispute outcomes. By disaggregating dispute outcomes to capture important theoretical distinctions among different types of “peaceful” resolutions to militarized disputes, we are able to generate new hypotheses about the effects of regime type on conflict escalation. Employing a multinomial logit analysis on disputes since 1816, we find that democracy has both monadic and dyadic effects on dispute escalation and that the effect of regime type varies with a states role in a dispute. Disputes with democratic initiators are less likely to escalate to violence because democratic initiators are more likely than nondemocratic initiators to obtain target concessions without employing force. Democratic targets, on the other hand, select themselves out of disputes by making concessions at a higher rate than nondemocracies, unless t...Drawing on arguments about the domestic political costs of using force and the ability of states to signal resolve, we develop a selection effects-based model of militarized interstate dispute outcomes. By disaggregating dispute outcomes to capture important theoretical distinctions among different types of “peaceful” resolutions to militarized disputes, we are able to generate new hypotheses about the effects of regime type on conflict escalation. Employing a multinomial logit analysis on disputes since 1816, we find that democracy has both monadic and dyadic effects on dispute escalation and that the effect of regime type varies with a states role in a dispute. Disputes with democratic initiators are less likely to escalate to violence because democratic initiators are more likely than nondemocratic initiators to obtain target concessions without employing force. Democratic targets, on the other hand, select themselves out of disputes by making concessions at a higher rate than nondemocracies, unless the dispute initiator demands a change in the targets governance or the territorial status quo. Both patterns provide evidence that democracies are more selective about the disputes they escalate to violence, rather than more pacific overall. We thank James Fowler, Robert Powell, Dan Reiter, Randolph Siverson, and Alastair Smith for valuable feedback as this project progressed. We are also grateful to the anonymous reviewers for their helpful comments and suggestions.

At What Price Victory? The Effects of Uncertainty on Military Intervention Duration and Outcome

I extend the implications of a rationalist model of war initiation to explore the effects of uncertainty about the cost of prosecuting a war to victory on the duration and outcome of military operations. When the attributes of a potential armed conflict create uncertainty about the human and material costs of attaining a states war aims, states are at risk of selecting themselves into long, costly, and ultimately unsuccessful military engagements. The more the actual costs of fighting exceed a states prewar expectations, the greater the likelihood that it will eventually be pushed beyond its cost-tolerance threshold and forced to unilaterally withdraw from the conflict before it attains its war aims. At the same time, states must fight longer before they arrive at accurate estimates of what it will cost to attain their objectives when the attributes of a conflict contribute to high levels of uncertainty.

The conditional impact of military intervention on internal armed conflict outcomes

Previous studies of internal armed conflict outcomes have found evidence that rebel-biased military intervention increases the likelihood of rebel victory, but little indication that pro-government interventions improve the odds of government victory. Our argument, grounded in a theory of the utility and limitations of military force in civil wars, anticipates that armed intervention increases the probability of victory for the supported side only when that belligerent’s primary challenge is a lack of conventional war-fighting capacity. Empirical analyses of internal armed conflicts from 1945 to 2010 support these expectations. Direct interventions in support of opposition movements have substantively large, robust effects on conflict outcomes. In contrast, government-biased interventions are only effective in increasing the odds of an outcome favorable to the government when the fighting capacity of rebel forces matches or exceeds that of the state.