64% Majority rule in Ducal Venice: Voting for the Doge

A recent result of Caplin and Nalebuff (1988) demonstrates that, under certain conditions on individual preferences and their distribution across society, super-majority rule performs well as a social decision rule. If the required super-majority is chosen appropriately, the rule yields a unique winner and voting cycles cannot occur. The voting procedure for electing a Doge in medieval Venice, developed in 1268, employed a super-majority requirement agreeing with the Caplin and Nalebuff formula. We present a brief history of the Venetian political institutions, show how the rule was employed, and argue that it contributed to the remarkable centuries-long political stability of Venice.