Is an Ultimatum the Last Word on Crisis Bargaining?

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Abstract. We investigate how the structure of the international bargaining process affects the resolution of crises. Despite the vast diversity in bargaining protocols, we find that there is a remarkably simple structure to how crises may end. Specifically, for any equilibrium outcome of a complex negotiation process, there is a take-it-or-leave-it offer that has precisely the same risk of war and distribution of benefits. In this sense, every equilibrium outcome of a crisis bargaining game is equivalent to the outcome of an offer in the ultimatum game. Consequently, if a state could select the bargaining protocol, it would choose an ultimatum or another protocol with the same result. According to our model, if states are behaving optimally, then we should observe no relationship between the bargaining protocol and the risk of war or distribution of benefits. An empirical analyses of ultimata in international crises supports this claim.