Larger Legislatures and the Cost of Political Brokerage: Evidence from Brazil.

This article shows that larger legislatures reduce the electoral power of incumbent parties in the executive. The electoral effects of legislature size have been largely overlooked by a literature that emphasizes its impact on policies. I estimate the effects of municipal council size on the performance of the local incumbent party in gubernatorial, presidential, and mayoral races in Brazil. The regression discontinuity design exploits variation from a law that set nonlinear council size caps after 2012. In a nutshell, every additional seat triggers a 5 percentage point vote loss for the candidates backed by the mayor's party. Additional evidence suggests that these losses are a consequence of a breakdown in the political brokerage relationships that often characterize developing democracies: in Brazil, mayors exchange patronage for the councilors' electoral support. Larger councils raise this transaction cost for mayors, more so when the council and mayor have unaligned electoral incentives at the state/national levels. [ABSTRACT FROM AUTHOR]