Throughout the world, liberal democracies are grappling with the growing salience of political cleavages that stem from claims made in the name of minority national, socio-cultural and ethno-cultural identities that seek greater recognition in the institutions of the nation-state. This book explores the debates centred on diversity through a normative and empirical analytical assessment of the political sociology of multinational democracies and the institutional possibilities associated with federalism. Gagnon argues that federalism, in both its institutional manifestations and its sociological properties, constitutes a promising avenue for the management of cohabitating political communities and for the affirmation of collective identities within states that are constituted by two or more nations. The author focuses on the case of Canada, in the broader context of other federal countries: Belgium and the United States, and countries in the process of federalization: Spain and the UK. This book will be of interest to students and scholars of political science, government and federalism.