Duverger's law

== English == === Etymology === Attributed to Maurice Duverger, French sociologist who published on the subject in the 1950s and 1960s. === Proper noun === Duverger's law (political science) The principle that plurality-rule elections (such as first past the post) structured within single-member districts tend to favour a two-party system, and that the double-ballot majority system and proportional representation tend to favor multipartyism. === Further reading === Duverger's law on Wikipedia.Wikipedia