War by coalition : the effects of coalition military institutionalization on coalition battlefield effectiveness

Abstract

What accounts for variation in the military performance of coalitions and alliances on the battlefield? This dissertation presents and tests a realist-institutionalist theory of coalition military effectiveness, which accounts for both the process of capability aggregation within military coalitions and its implications for coalition fighting effectiveness. It posits that variation in the design of coalition institutions for political-military planning, command relationships and information exchanges significantly affects the ability of member nations to fight alongside each other on the battlefield. According to the theory, coalition military institutions provide the key mechanisms through which coalition members manage intra-alliance uncertainties and fears, thereby allowing for closer coordination of their war effort. The most effective military coalitions adopt joint political-military coalition planning, unity of command with an integrated command staff, and the fluid exchange of information among coalition nations. The study tests this theory through a mixed-methods approach, complimenting a medium-n statistical analysis with two detailed case studies of coalition wars fought under conditions chosen to provide maximum theoretical leverage. The medium-n statistical analysis examines all interstate coalition wars waged between 1816 and 2007 using the Correlates of War Inter-state War Data (version 4). Using primary documents, memoirs and battle histories, the study tests realist-institutionalist theory in two empirical cases: France and Britain in the First World War (1914-1918) and France and Britain in the Battle of France (May-June 1940). The main finding is that variation in the design of coalition military institutions accounts for differences in coalition battlefield effectiveness both across and within coalitions over time. The study makes three principal contributions. First, it offers the first serious treatment of coalition military effectiveness in the academic literature. Unlike other research, it expands beyond national military effectiveness to consider the coalition dimension. Second, the study contributes to a growing body of research suggesting the importance of non-material variables to explanations of military effectiveness, drawing attention to the critical importance of coalition military institutions for combat power. Finally, the study informs the public policy debate, suggesting whether the US and other allies could achieve battlefield success more quickly, with fewer casualties and at lower costs if it acted through ad-hoc military coalitions or institutionalized alliances.