The Cost of Security: Foreign Policy Concessions and Military Alliances

摘要

One way states can mitigate external threats is by entering into military alliances. However, threatened states are reluctant to enter into military alliances because alliance membership can require significant policy concessions. An important and unanswered question is: when will states be willing to make policy concessions in exchange for military alliances? This is the question that is investigated in this project. To address this question I develop a simple three actor bargaining model of alliance formation that endogenizes both external threat and policy concessions. I test the model's implications with two sets of large N analyses and find strong support for the hypotheses. The first set of empirical analyses uses a novel research design that takes into account the attributes of challengers to evaluate states' alliance formation decisions. The second set is based on the same research design and provides one of the first analyses of foreign policy concessions among alliance members. The results suggest that threatened states are willing to make more concessions in exchange for an alliance when they are unlikely to defeat their challengers alone and when their allies have a large effect on their probability of defeating their challengers. This research highlights both the security and non-security motivations for alliance formation and demonstrates that alliances have important influences beyond international security.