Electoral Systems and System Reforms in Latin America

Abstract

Electoral systems impose incentives for relationships between parties and relationships within parties. In interparty terms, weak systems encourage many parties to enter and voters to vote sincerely for their most preferred options. Strong systems discourage many parties from entering and encourage voters to think strategically about viability (the likelihood a preferred option will win seats). In intraparty terms, centralized systems empower party leaders and put an emphasis on the party’s shared reputation. Individualistic systems empower individual candidates and members of congress and put an emphasis on their personal reputations. The individual rules examined when defining system incentives include ballot type (can voters choose among copartisans), the level to which votes are pooled before seats are awarded, the number and level at which votes are cast, district magnitude (the number of seats to be decided in a district in a given election), and legal thresholds (predefined vote total barriers to being awarded seats). The electoral systems used to elect lower houses, upper houses (where they exist) and presidents in Latin America are located in a two-dimensional space based on these incentives. In interparty terms, weak systems outnumber strong ones in the region. In intraparty terms, there is a great deal of diversity with centralized systems slightly outnumbering individualistic ones. Instances of electoral reform are captured as changes in incentives or movements in this space. Reforms are frequent but no clear pattern emerges in terms of countries across the region converging toward imposing similar electoral incentives.