Optimal voting rules for international organizations, with an application to the United Nations

Abstract

This paper studies a self-enforcing mechanism for an international organization that interacts repeatedly over time. A random shock determines which countries would be in favor of or against taking a collective action. If the organization wants to take the action, incentives must be provided. The optimal stationary equilibrium is equivalent to a mechanism characterized by voting weights. When the discount factor is not too high, the voting weights are random. Moreover, within a class of parameters, the optimal mechanism mimics the way voting power is distributed among United Nations members via Security Council seats. That is, the model rationalizes the existence of a council with permanent members who have veto power, nonpermanent members, and the exact number of permanent and nonpermanent members observed at the Security Council.