Where Rawls’s The Law of Peoples addresses war and the use of force then his position has often been identified closely with Walzer’s restatement of just war theory, as both positions appear to take nation-states, and the conflicts between them, to be the bedrock of the international system. On the other hand, Kant’s notion of a peaceful federation of states presents us with the notion of a world without war and where the international system is transformed. This article argues that Rawls’s account of the use of force is better understood if we read it with an eye to its resonances with Kant rather than with Walzer. Doing so rewards us with a clearer understanding of central aspects of Rawls’s account of just war and vision of international politics.