Fighting friends

For much of history, multinational wars have been the norm rather than the exception. Yet the study of these wars has been largely ignored. Existing scholarship on wartime alliances focuses almost exclusively on the causes of alignment or the onset of conflict ignoring the conduct and consequences of these arrangements. Wartime partnerships exhibit enormous variation in their structure, however. What accounts for the varied multinational security arrangements states adopt in wartime? I argue that the choices states make in constructing these wartime partnerships have important consequences for both the conduct and outcome of conflicts. Following the institutional design literature, I argue that these differences are purposeful and originate from the rational calculations and strategic interactions among the actors creating them. I focus on one design feature of multinational military structures in particular, that of command and control (C2). The enormous variation visible in multinational command and control structures in wartime begs two questions: First, why do states adopt different command and control structures? Second, what drives actors to abandon one structure in favor of another? To answer these questions, I develop a theory of failure-driven change. Because conventional wisdom suggests that greater cooperation is beneficial, yielding gains for all, the puzzle naturally arises as to why all wartime partnerships don’t start out in the tightest configuration possible, that of unified command. After all, the benefits of greater wartime integration are seemingly vast; from the reduction of uncertainty and transaction costs to the conferral of legitimacy, tightly integrated arrangements confer distinct advantages. Despite the many benefits wartime integration confers, however, I argue states are reluctant to adopt unified command for fear of having to surrender operational control over their military forces. Yet even a cursory examination of wartime multinational partnerships reveals that states do sometimes enter into more integrated command relationships, leading to the (second) question of what motivates them to do so. Here, I argue that one factor in particular, that of battlefield performance, leads states to abandon their intrinsic reluctance toward unity of command. Specifically, I argue that when faced with military defeat on the battlefield, states often respond by experimenting with new command and control arrangements. The learning process is often tentative and slow yet over time leads to greater integration. Additionally, I argue that greater integration in multinational command and control structures is correlated with improved military performance. In short, failure leads to adaptation which then leads to success. To test my theory of institutional learning, I employ comparative historical analysis, specifically process tracing and the congruence method. The universe of cases consisted of all multinational wars since 1816, some 38 conflicts. However, because a number of these cases featured multinational parties on both sides, this yielded a total of 43 cases. Three cases were chosen on the basis of representativeness and variation on the dimensions of theoretical interest. The cases examined were the Entente and Central Powers in World War I and the UN coalition in the Korean War. Overall, the cases provide strong support for my theory of wartime learning. The findings suggest that failure is a key determinant of wartime integration.