Over the last 20 years, cosmopolitan theories have been benefiting greatly from the dialogue between defenders and critics of world citizenship. Yet, the decidedly polemic aspect of this debate, while allowing for intellectual progress, is also responsible for overdrawn generalizations. Instead of entering into the debate directly, this article attempts to refute a specific anti-cosmopolitan claim raised by Chantal Mouffe. Her realist objection to cosmopolitanism, derived from the conceptual framework of agonistic pluralism, is mistaken at a crucial point: a firm dichotomy between politics and morality cannot provide an alternative to theories of world citizenship, because Mouffe’s embrace of multipolarity as a principle of global politics must equally appeal to a set of universal norms governing international relations. This article argues that even the realist model of multipolarity needs to conceive of a minimal morality to create the symbolic ground on which various power centres can be held accountable.