Maurice Duverger proposed, in 1951, that the number of parties in a party system is a function of “mechanical” and “psychological” effects of the electoral laws governing such system. More specifically, majoritarian ballots of a single round would tend to lead to a two-party system, and proportional ballots to a multiplication of parties. For over 60 years, the propositions of Duverger were criticized, extended, and tested by numerous researchers in several countries. Surprisingly, however, this debate had little impact in Brazil, especially with respect to majoritarian elections. In this article, the author essays to fill such gap, using tests intended to identify the effects of Duverger’s Law in Brazilian majoritarian elections, discussing how these effects depend on the voter’s strategic action vis-à-vis the strategies of the party elites.
Duverger’s Law; Political parties; Electoral coordination; Strategic voting; Elections
