Duverger's law

Duverger's law ( Loi de Duverger ), named after the French jurist and political scientist Maurice Duverger is the suspected law, after a relative majority system to form a two-party system leads. In reverse is true, that a system of proportional representation leads to a variety of parties.

The idea behind this conjecture is that in a relative majority system in single-member constituencies only a few candidates have a realistic chance of being elected. A rational thinking voter casts his vote then not the candidate of the party which he personally preferred, but another candidate who has more chance of success. So the voices focus on two parties, a rather right and left rather. This effect was formulated by Duverger in several papers in the 1950s and 1960s, and it added to the literature towards commonly known as Duverger's Law.

The law has, however, now widely criticized. The effect come into being only when there are few lines of conflict in society, typically between rich and poor ( labor and capital). The profitable a social democratic party on the one hand and a conservative-liberal on the other. In most societies, but are still add more lines of conflict, for example, denominational, ideological or cultural nature is also important, whether concentrated minorities live in different regions (and hence can conquer constituencies ) or scattered across the land.

As the classic example of Duverger's law was Great Britain, 1974 and 2010, however, succeeded the Liberal Party and the Liberal Democrats as the third party to achieve a majority critical number of parliamentary seats. The government coalition between the Conservative Party and the Liberal Democrats in 2010 occupied the criticism of this law. Likewise, India also selected by single-member constituencies, where a large number of small regional parties comes into Parliament.