In the last three decades, liberal political philosophy has been increasingly concerned with the nature and extent of the moral responsibilities of members of different political communities to each other. John Rawls contributed to this debate in his final book, The Law of Peoples (LP). In LP, Rawls refused to extend his account of domestic distributive justice to international politics and argued that some non-liberal (yet decent) peoples can be membersin good standing of the international community. Many of Rawls’ critics maintain that this evidences a double standard, and accuse LP of being an incoherent extension of Rawls’ political philosophy to global politics. In this book I show that the opposite is true. I start by underlining the main discontinuities between Rawls’ accounts of domestic and international justice. I then show that these discontinuities can be explained by tracing the evolution of the idea of public justifi- cation in Rawls’ work. Rawls’ two theories of justice are the application of the same idea – public justification – in different political contexts.