Why does the United States sometimes seek multilateral support for its military interventions? When does it instead sidestep international institutions and intervene unilaterally? In Coalitions of Convenience, a comprehensive study of US military interventions in the post-Cold War era, Sarah Kreps shows that contrary to conventional wisdom, even superpowers have strong incentives to intervene multilaterally: coalitions confer legitimacy and provide ways to share the costly burdens of war. Despite these advantages, multilateralism comes with costs: multilateral responses are often...

Why does the United States sometimes seek multilateral support for its military interventions? When does it instead sidestep international institutions and intervene unilaterally? In Coalitions of Convenience, a comprehensive study of US military interventions in the post-Cold War era, Sarah Kreps shows that contrary to conventional wisdom, even superpowers have strong incentives to intervene multilaterally: coalitions confer legitimacy and provide ways to share the costly burdens of war. Despite these advantages, multilateralism comes with costs: multilateral responses are often...