International Unions

Abstract

We model an international union as a group of countries deciding together on the provision of public goods or policies that generate spillovers across members. The trade-off between benefits of coordination and loss of independent policymaking endogenously determines size, composition and scope of the union. Policy uniformity reduces the union's size, may block enlargement processes and induce excessive centralization. We study flexible rules with non-uniform policies that reduce these inefficiencies focusing on arrangements relevant in the context of existing unions or federal states, like enhanced cooperation, subsidiarity, federal mandates and earmarked grants.