Allan C. Stam

The Duration of Interstate Wars, 1816–1985

We present a model of war duration which incorporates both realpolitik and domestic political variables. We hypothesize that strategy, terrain, capabilities, and government type, among other variables, will play key roles in determining the duration of war. We test these hypotheses using hazard analysis and find empirical support for our key arguments. We find that the realpolitik variables play a greater role than regime behavior and type in determining war duration. We also find that historically, on average, mobilization and strategic surprise have little effect on war duration and that wars are not duration dependent.

Bargaining and the Nature of War

A model of bargaining embedded within a random-walk model of warfare is developed. The conflict model contains aspects of both lottery-based and war-of-attrition models of conflict. Results show that future disputes are less likely to lead to armed conflict following long rather than short wars. Furthermore, should a subsequent dispute lead to armed conflict, the higher the cost and the longer the previous war, the shorter the conflict is likely to last.

The Declining Advantages of Democracy: A Combined Model of War Outcomes and Duration

The authors estimate a dynamic model to assess the effects of democracy on war outcomes and how these effects vary over time. Using quantitative data drawn from interstate wars between 1816 and 1990, the authors demonstrate that the wartime advantages that accrue to democratic states are fleeting. In the short run, democracies are more likely to win than are their autocratic opponents. However, although they are at an apparent disadvantage in short wars, autocracies are far less likely to quit as time passes. This willingness to continue fighting ultimately leads to the result that after roughly 18 months have passed, the advantage passes to the autocrat. Democracies at that point become far more likely than autocratic states to quit and more willing to settle for draws or losses. The authors also find that relationships between war outcomes and a number of control variables such as military-industrial capacity and military strategy vary over time.

Research Design and Estimator Choices in the Analysis of Interstate Dyads

Researchers face three basic questions when testing theoretically driven hypotheses. First is research design: for example, what population should be analyzed, what sample should be drawn from that population, and what cases should be excluded from the sample? What statistical estimator should one use? What set of control variables should one employ? Results drawn from several permutations of the Correlates of War Militarized Interstate Dispute data set are compared using three statistical models. For some theories and variables (international institutionalism—intergovernmental organization and alliance membership; realism—balance of power; expected utility theory—international interaction game equilibria), research design and estimator choices substantially influence the findings. For others (trade and democratic peace theory), the relationship between the dependent and independent variables is relatively impervious to research design and estimator choices.

In the Nick of Time: Conflict Management, Mediation Timing, and the Duration of Interstate Disputes

This paper develops a theoretical argument linking time and the timing of conflict management efforts to dispute duration. We test competing hypotheses on conflict data drawn from disputes in the post-1945 period. Our analysis demonstrates that the effects of mediation vary substantially over the course of a dispute. Specifically, we note that mediation has a curvilinear relationship with time and the ending of disputes. Mediation efforts that occur soon after disputes begin have the best chance of reducing expected future dispute duration. Following this initial period, subsequent mediation efforts lead to longer rather than shorter disputes. After a long period, mediation again leads to shorter rather than longer disputes. We also find that there should be consistency in the mediators used to manage a conflict rather than shifting personnel to interject new ideas.

Democracy and Battlefield Military Effectiveness

Why do democracies win the wars they fight? The authors explore this question by examining whether the armies of democratic states fight with higher military effectiveness on the battlefield, testing two general propositions: that the higher legitimacy of democratic states spurs superior individual soldiering and that democratic militaries are likely to have higher organizational efficacy. The authors test their propositions on a comprehensive set of major battles from 1800 to 1982, using data compiled by the Historical Evaluation and Research Organization. The authors find that the armies of democratic states tend to fight with marginally better logistics, substantially better initiative, and superior leadership. They also find that all three of these advantages dwindle as wars lengthen and interpret the results as indicating that although soldiers are not more willing to die for democratic governments, the emphasis on individual initiative in democratic culture generates important advantages on the battlefield.

Political Institutions, Coercive Diplomacy, and the Duration of Economic Sanctions

A theory of sanction duration that focuses on differences between democratic and nondemocratic states in the structure of leaders’ support coalitions is tested, using a hazard model to analyze a data set of 47 sanction events with 272 observations. Results show that leadership change strongly affects the duration of sanctions only in the case of nondemocratic states. Leadership change in democratic states is unrelated to the duration of sanctions; however, leadership change in nondemocratic sender and nondemocratic target states is strongly related to the ending of economic sanctions.

Identifying the Culprit: Democracy, Dictatorship, and Dispute Initiation

Peceny, Beer, and Sanchez-Terry (2002) find that interstate dyads containing a democracy and a personalist dictatorship are more likely than other types of dyads to experience militarized disputes. They argue that this is because democracies are especially likely to challenge personalist dictatorships. Unfortunately, they do not identify which state in a conflictual dyad initiated the dispute and so cannot present data to support their claim. We improve on their research design by using “directed dyads” to identify potential initiators. We confirm their finding that democracy–personalist dictatorship dyads are particularly conflict-prone, but we also disprove their argument that democracies attack dictators, as we find that personalist dictatorships are more likely to challenge democracies, but not vice versa. We also find that other kinds of autocracies, namely, military regimes and single-party regimes, are more likely to challenge democracies than vice versa. Our findings have important implications for understanding the relationships between regime type and international conflict.The authors thank Caroline Beer very much for assistance with data.

A Universal Test of an Expected Utility Theory of War

Bueno de Mesquita and Lalmans version of an expected utility theory of war has become one of the most widely cited theories of international conflict. However, the testing of the theory has lagged behind its theoretical development. In its most sophisticated formulation, the theory has been tested on only 707 dyad-years, all drawn from Europe between 1816 and 1970. We present a test of the expected utility theory of war (as developed in War and Reason ) on the international system from 1816 to 1984. Specifically, we examine the relationship between the main equilibrium variables derived under the “domestic variant” of the international interaction game and behavioral outcomes using multinomial logit. We find that the equilibria correlate with actual behavior in both the set of all dyads and a subset of politically relevant dyads, even after including a set of control variables. The relationship is somewhat less clear among the population of all interstate-directed dyads, however, with key equilibrium variables having smaller effects at increasing the odds of interstate conflict among all dyads. We also present a new software program, EUGene , which generates expected utility data and can serve as an important data management tool for international relations researchers.

Understanding Victory: Why Political Institutions Matter

In our book, Democracies at War, we asked the question: Why do democracies tend to win the wars they aght? We conarmed this pattern, arst noted by David Lake in his “Powerful Paciasts” article, using statistical tests and numerous historical cases.1 Notably, this phenomenon confounds the traditional realpolitik fear that democratic liberalism is a luxury that states may be unable to afford. Our basic answer to the question is that democracies tend to win because they put themselves in a position to do so. The constraints that oow from democratic political structures lead the executives of liberal democracies to hesitate before starting wars, particularly wars where victory on the battleaeld appears to be less than clear-cut. Democracies’ willingness to start wars only against relatively weaker states says nothing about the actual military efaciency or capacity of democratic states. Rather, it says that when they do start a aght, they are more likely to pick on relatively weaker target states. We also and, however, that in addition to this “selection effects” explanation of democratic success, democratic armies enjoy a small advantage on the battleaeld. Michael Desch, a prominent realist scholar, reviews these claims in his article “Democracy and Victory: Why Regime Type Hardly Matters.”2 His assertion that regime type is irrelevant to the probability of military victory is consistent with the broader realist agenda, which argues that domestic politics matters little in the formation of foreign policy or the interactions between states. Desch makes a valuable contribution in advancing the debate over this question. There are many points about which Desch and we agree. Democracies do Understanding Victory