Explores the roots and implications of the 'constructivist turn': the reorientation of scholarship on mass democracy toward the constitutive or mobilising aspects of political representation. Traces the roots of the constructivist turn in the distinct (and competing) traditions of Continental and Anglo-American Western political thought. Critically examines the normative challenges raised by the constructivist turn. Debates the adequacy and consequences of the concept for Western democratic institutions, movements and norms. Features a new English translation of Claude Lefort's previously untranslated 'Democracy and Representation'.