Division of the Humanities and Social Sciences California Institute of Technology Pasadena, California 91125 Political Confederation

Using a spatial model, we compare different rules for aggregating preferences across confederated districts, under the assumption that voters have private information and face uncertainty about the distribution of preferences of other voters. Our model includes, as special cases, systems of local representation in national assemblies and parliaments and international legislatures with rep­ resentatives from member states. We show how induced preferences over the degree of centralization and the method of representation (proportional vs. equal representation of districts) vary systematically across voters and dis­ tricts, depending on such factors as relative size of the districts, the number of districts, and the variance of underlying policy preferences. We show that each voter has an ideal confederation in which representation consists solely of equal representation. These ideal confederations vary across voters, but are independent district size. Moderate voters prefer a higher degree of centralization than extreme voters. Preference for centralization is increasing in the number of districts and decreasing in the variance of voter ideal points. With two districts, majority rule equilibria always exists and can have some degree of proportional representation. With three or more districts, majority rule equilibrium often fails to exist. Nonexistence arises due to cycling in the two dimensional-Centralization x Representation-space of confederations.