We propose an explanation for the most prevalent form of democratic breakdown after the Cold War: the subversion of democracy by incumbents. In both democratization research and democracy promotion practice, the public is assumed to serve as a check on incumbents' temptations to subvert democracy. We explain why this check fails in polarized societies. When polarization is high, voters have a strong preference for their favorite candidate, which makes it costly for them to punish an incumbent by voting for a challenger. Incumbents exploit this lack of credible punishment by manipulating the democratic process in their favor. Our analysis of an original survey experiment conducted in Venezuela demonstrates that voters in polarized societies are indeed willing to trade off democratic principles for partisan interests and that their willingness to do so increases in the intensity of their partisanship. These findings suggest the need to re-evaluate conventional measures of support for democracy and provide an answer to a fundamental question about its survival: When can we expect the public to serve as a check on the authoritarian temptations of elected politicians?