I have suggested that liberalism is committed to a cosmopolitan understanding of distributive justice. That is, liberals ought to take distributive principles to apply to all individuals of the world equally regardless of their nationality and other contingent facts about them. In short, liberals ought also to be cosmopolitan liberals. I will refer to this as the “traditional view,” meaning by this label not that there is a strong historical connection between liberalism and cosmopolitanism (because this is not necessarily the case), but that the universalism commonly associated with liberal justice is widely seen to entail the cosmopolitan ideal.

But in recent years, the traditional view has come under challenge from within liberalism itself. A growing number of liberal theorists argue that implicit in liberalism is a theory of nationalism. The resurgence of nationalist movements in different parts of the world in recent years and the renewed challenges of multiculturalism and migration within liberal democracies have prompted a burgeoning interest among liberal theorists in the idea of nationalism. One outcome of this confrontation with nationalism is the growing consensus among contemporary liberal theorists that liberalism and nationalism, far from being contradictory ideals as once commonly thought, are not only compatible but indeed mutually reinforcing ideals. As nationalism needs liberalism to tame it and to set moral constraints on it, so liberalism needs nationalism in order to achieve its ends.