Presidentialism, Multiparty Systems, and Democracy: the Difficult Equation

This paper argues that the combination of a multiparty system and a presidential system is inimical to stable democracy. The paper presents empirical evidence that shows that few (4 of 25) stable democracies have presidential systems. Several features of presidential systems contribute to explaining why so few have become stable democracies; this paper focuses particularly on the possibility that presidential systems are more prone to immobilism, weak executive power, and destabilizing executive/legislative conflict than parliamentary systems. The paper then shows that among all of the cases (past or present) of stable presidential democracy, only one—the Chilean—had a multiparty system. In presidential democracies, two-party systems are more capable of avoiding immobilism and intense legislative/executive conflict because they facilitate the formation of a government with a majority (or close to it) in congress, and also because ideological polarization is less likely with only two parties.