Military coalitions are ubiquitous. The United States builds them regularly, yet they are associated with the largest, most destructive, and consequential wars in history. When do states build them, and what partners do they choose? Are coalitions a recipe for war, or can they facilitate peace? Finally, when do coalitions affect the expansion of conflict beyond its original participants? The Politics of Military Coalitions introduces newly collected data designed to answer these very questions, showing that coalitions - expensive to build but attractive from a military standpoint - are very often more (if sometimes less) than the sum of their parts, at times encouraging war while discouraging it at others, at times touching off wider wars while at others keeping their targets isolated. The combination of new data, new formal theories, and new quantitative analysis will be of interest to scholars, students, and policymakers alike.

'The Politics of Military Coalitions is an important addition to theoretical and empirical research on bargaining and war. What sets Scott Wolford’s book apart is his ability to focus on bargaining among partners and bargaining with enemies simultaneously. In Wolford’s hands, the complex political dynamics of multilateral military coalitions become understandable. This book is recommended reading for all scholars of international cooperation and international conflict.'

Ashley Leeds - Rice University, Houston

'States form coalitions during crises to advance common interests through the coordination of their actions. They are not explicit commitments as are alliances, but they require more of the parties than alignment of interests. Scott Wolford masterfully analyzes the strategic logic of coalitions, showing when they form, how they complicate coercive bargaining, how they fight together, and how long they last afterwards. It is a major contribution to our understanding of international conflict.'

James Morrow - A. F. K. Organski Professor of World Politics, University of Michigan