There exists a longstanding debate over the global institutional implications of Immanuel Kant's political philosophy: does such a philosophy entail a federal world government, or instead only a confederal ‘league of nations’? However, while the systematic nature of Kant's tripartite ‘doctrine of right' is well recognised, this debate has been conducted with all but exclusive focus on ‘international right' in particular. This article, by contrast, brings ‘cosmopolitan right' firmly into view. It proceeds by way of engagement with the two Kantian (...) arguments made in defence of a ‘league of nations’ in discussion of international right, each of which appeals to aspects of states’ supposed ‘personhood’: the first appeals to states’ distinctive moral personality; the second to states’ physical manifestation. The article considers what happens when we assess these arguments not just in light of the demands of international right, but also in light of cosmopolitan right, and thus in light of public right more comprehensively. The answer is that such arguments cannot succeed as full defences of a league of nations. Indeed, when we assess such arguments with cosmopolitan right in view, they point instead – either tentatively or definitively – in the direction of world government. (shrink)