The Politics of Diplomacy: How the United States Builds Multilateral Military Coalitions

How does the United States build multilateral military coalitions? Conventional wisdom focuses on the role of formal alliance structures. Allies band together because they share threat perceptions, political ideology, norms, and values. I argue instead that US-led coalition-building efforts are influenced by the entirety of bilateral and multilateral ties that connects the United States with a third party. The breadth of institutions matters because it allows officials to gather information on the potential coalition partner’s deployment preferences beyond straightforward security considerations—such as what kind of economic and political considerations affect its willingness to join the coalition. Diplomatic embeddedness also helps American officials identify linkages between military and non-military interests. This facilitates the construction of side-payments. I find evidence for my argument by using an original dataset including all US-led multilateral coalitions in the pre– and post–Cold War era. I complement the quantitative analysis with a case study on US coalition-building efforts for the Korean War.