Minimum Winning Coalition, in Politics

Abstract

The central debate in coalition theory is between those who hypothesize that politicians seek to maximize vote share and those who hypothesize that politicians seek to gain just enough support to win and no more. This debate is central to the investigation of legislative coalitions and coalition governments, especially in parliamentary systems. Minimal winning coalitions, that is, alignments of parties or politicians just large enough to defeat rivals and no larger, ensure that politicians make as few legislative concessions as possible while still controlling sufficient support to maintain governmental authority and pass legislation. Larger than minimal winning coalitions reduce the vulnerability of leaders to defections by individual legislators or small, highly issue focused parties, but at the expense of greater legislative concessions. By reviewing the coalition literature it is possible to understand when minimal winning coalitions make most sense theoretically and when they arise in reality.