Mexico: Designing Electoral Rules by a Dominant Party

The very long-term ruling party of Mexico, the Institutional Revolutionary Party (PRI), has developed a number of electoral reforms since the early 1960s by achieving successive compromises with the opposition parties. On the one hand, electoral fraud was reduced and electoral competition was increased through a very slow and gradual process of successive reforms. On the other hand, the PRI crafted electoral rules aimed at protecting its own dominance. Basically, plurality rule in single-member districts was kept in place while adding proportional representation in multi-member district races for a minority of total seats. The PRI followed a divide-and-rule strategy, offering short-term electoral benefits to a fraction of the opposition, in exchange for rules that discouraged coordination among the opposition parties and which would eventually make the incumbent party more difficult to dislodge. Opposition political actors abided by the new rules in the expectation of generating greater political openings. But it was not until the 1997 congressional elections that the PRI lost its absolute majority in seats and not until the 2000 presidential election that an alternative candidate finally won. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.