Duvergerlagen

Duvergerlagen is a term used in political science and electoral studies to describe the relationship between electoral systems and the party system. Specifically, it refers to the tendency of plurality or majoritarian electoral systems, often referred to as "first-past-the-post" systems, to produce a two-party system. This phenomenon is named after the French political scientist Maurice Duverger.

The core idea behind Duverger's Law is that voters, in an effort to avoid "wasting" their vote on a candidate or party they believe has little chance of winning, tend to coalesce around the two most viable contenders. This strategic voting behavior, combined with the electoral system's tendency to amplify the victory of the leading candidate and penalize smaller parties, leads to a consolidation of political power within two dominant parties.

Conversely, proportional representation electoral systems, which allocate seats based on the overall percentage of votes received by each party, are generally associated with multi-party systems. In these systems, smaller parties have a greater incentive to form and compete, as their votes are more likely to translate into representation.

While Duverger's Law is a widely cited concept, it is not an absolute rule and has been subject to various refinements and criticisms. Other factors, such as historical traditions, social cleavages, and campaign finance laws, can also influence the number of parties that emerge in a political system. Nonetheless, the law remains a significant framework for understanding the impact of electoral rules on party competition.