The story
Attributed to Maurice Duverger, French sociologist who published on the subject in the 1950s and 1960s.
Etymology from Wiktionary, CC BY-SA 4.0.
Duverger's law
Today it means: 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. Full definition →