Reasons for Fragmentation: Party Coalitions and Strategies Regarding Simultaneous Majoritarian and Proportional Elections

ABSTRACT

Institutionalist explanations about the format of party systems assert that coincident presidential and congressional elections, in the presence of small numbers of presidential candidates, reduce the number of parties in the dispute to the legislature. Despite the system of simultaneous elections for president and deputies established in 1994 and the stabilization of the number of viable presidential candidates, party fragmentation has been systematically increasing in Brazil. This article tries to understand the reasons for the detachment between the structure of the competition for the presidency and the electoral dispute for the Chamber of Deputies. The article points to a diffuse coattail effect that allows parties without viable candidates to win electoral benefits by participating in coalitions in the presidential race. To win the presidential race, parties capable of competing with their own candidates form broad coalitions, which require the allies to be compensated in simultaneous disputes. Intra-collective coordination produces electoral losses for the head of the slate in the elections of federal deputies, while at the same time boosts the performance of the related parties. The article tests these hypotheses through a series of statistical models that estimate the determinants of national party voting in all disputes for the Chamber of Deputies between 1994 and 2014.

party system; presidentialism; presidential elections; coalitions