In this policy brief, Cas Mudde of the University of Georgia sets out a definition for populism and argues that, contrary to claims by the Tea Party and other populist movements around the world, populism is in fact theoretically opposed to constitutionalism. He reasons that, while populism is essentially democratic, by adopting a form of extreme majoritarianism, it is contrary to the limits placed on both popular sovereignty and majority rule that are integral to constitutional principles.
Mudde describes populists as taking an opportunistic approach toward constitutions, clinging to the constitutional protection of their minority rights, while rejecting those of other minorities on the basis of the democratic argument of majority rule.
The brief identifies flaws in the often vague and moralizing liberal attacks on populist movements, and instead makes recommendations that liberal democrats should emphasize the illiberal aspects of populism, while emphasizing the importance of liberal aspects of the political culture and system.