The politics of alliance: Security tradeoffs in enduring interstate rivalries.

Abstract

States facing threats to their security may respond by acquiring arms or relying on allies or both. Acquiring arms is costly, but a state that has no allies maintains greater political autonomy. Alliances provide promises of military support in exchange for political concessions. A state that relies on allies risks abandonment or entrapment. Deciding between arms and alliances is thus a question of tradeoffs. I model a state's decision as a simple consumer choice. The constrained optimization yields testable hypotheses about when a state should acquire more arms and when it should tighten its alliances. The stronger the ally, the less costly the political concessions the ally demands, and the greater a state's pool of resources, the tighter its alliance should be. The weaker the ally and the more costly the alliance support, the more arms the state should acquire. I test the hypotheses by examining the security policies of Austria-Hungary and France, prior to World War I, and Syria and Israel, in the contemporary period. All four countries' security policies are consistent with the theoretical predictions.