Robert Michels's seminal treatise Political Parties: A Sociological Study of the Oligarchical Tendencies of Modern Democracy (1911) offers an important theoretical exposition of the core belief that underlies populist politics: namely, that the elites (inevitably) capture democracy from the common people. Michels's disillusionment with the elitist betrayal of democracy led the sociologist to embrace Mussolini's fascism, a biographical note that seems to validate contemporary fears about populism's logical endpoint. Our answer to the theoretical challenge raised by Michels's "iron law of olig...