Gerrymandering Opposition: Minority-Concentrated Districts and Electoral Competition in Mexico

Abstract

Can institutions that are designed to improve minority representation also have an effect on electoral competition? We address this question by examining how minority-concentrated districts (MCDs)—designed to empower indigenous populations—affected minority participation and party competition in Mexico. Using an original dataset and a matching design that helps alleviate causal inference problems inherent to observational studies, we find that MCDs had no effect on minority participation but enhanced electoral competition. Field-research reveals that MCDs weakened one-party dominance by assembling minority voting blocs that were amenable to opposition-party appeals. More broadly, our results suggest that the mobilization of minority voting blocs can promote electoral competition in transitional democracies.