The Political geography of government formation: Why regional parties join coalitions

Abstract

Political parties differ in the geographic distribution of their support. This article argues that a regionalized distribution of a party's votes facilitates its participation in government, because it produces a tendency to prioritize demands for locally targeted goods that are more conducive to the negotiation of reciprocal logrolling agreements with potential partners. Using a measure based on the Gini coefficient, I empirically evaluate the extent to which the geographic concentration of votes plays a role in the formation of governments, taking Spanish local elections from 1987 to 2011 as a test bed. With around 500 formation opportunities and 20,000 potential governments, multinomial choice models are estimated (conditional and mixed logits) and a very sizable effect is documented: A one-standard deviation increase in the electoral geographic concentration of the members of a potential government almost doubles the likelihood of its formation. These findings are relevant for students of government formation, regional parties, and political geography.