When Immanuel Kant first conceived his famous, ironically-titled essay on “Perpetual Peace” (1795/1983), the notion of political regionalism had not yet been invented by political philosophers, much less put into effect. By now that slim pamphlet has become paradigmatic for discussion of the normative foundations of global multilateralism. When the League of Nations was founded after World War I, it served as a blueprint for the League’s vision, and it has remained an inspiring reference for reflections about the foundations of a just international system ever since. Does the essay still offer guidance for understanding regions and civilizations? Kant drew on Enlightenment philosophy to sketch the outlines of what he took to be a just (based on equality), prudent, and stable multilateral world order. Even though its intellectual roots lie so far in the past, it would seem that, at least in their substance and normative content, his ideas are insightful and constantly inspiring for all levels and variants of international multilateralism. They provide a solid middle ground in the contemporary debate that is characterized by the antipodal and extreme positions of Samuel Huntington (1996) and Francis Fukuyama (1992), both of which have proven to be too simplistic to help us grasp the current political–cultural reality in the world. The question is, are the world’s geo-cultural regions quasi-natural, homogenous cultural blocs? Alternatively, are they malleable and dynamic entities on an ineluctable historical path toward convergence on the European model? Or could they be something else entirely?