Constructing a theory of global socioeconomic justice presents both conceptual and normative challenges. Should one strive for the uncompromising moral and humanitarian ideal of equality, or do the difficulties of international governance demand a more pragmatic understanding of justice? In “The Problem of Global Justice”, Thomas Nagel defends what he calls the political conception of global justice. Nagel’s account holds that socioeconomic justice only exists within states, not between them. From this it follows that developed states do nothing unjust when they decline to transfer wealth to developing states. While Nagel’s account has some initial appeal, I find cosmopolitanism to be a far more compelling account of global socioeconomic justice. My defence has three parts. First, I argue that Nagel misunderstands the relationship between justice and sovereignty under cosmopolitanism. I then demonstrate that, properly understood, cosmopolitanism can justify limiting the scope of socioeconomic justice to state borders through the right of self-determination. I conclude by highlighting that cosmopolitanism can not only limit socioeconomic justice in the same way Nagel’s political conception can, but that it can do so with a clearer rationale and greater applicability to reality.