Electoral Systems and the Number of Parties in Postcommunist States

Scholars studying electoral systems have consistently found that single-member plurality elections tend to constrain the number of parties operating in a polity to a much greater extent than multimember proportional representation systems. This article tests this hypothesis in the post-communist context by examining the effects of proportional representation and single-member district elections on the number of parties in five postcommunist states. It is shown that some postcommunist states, most notably Poland and Hungary, have followed the standard pattern of party consolidation over time in reaction to incentives of electoral systems, while others, most notably Russia and Ukraine, have not. The author argues that the different effects of electoral systems can be attributed to different levels of party institutionalization found in postcommunist states. These findings have policy implications. Under conditions of extreme party underdevelopment, the electoral system that promotes the use of party labels—proportional representation—may be more effective than the plurality system in constraining the number of parties, provided a legal threshold is used. This runs counter to the conventional wisdom that plurality elections offer the greatest constraint on the number of parties.