This paper focuses on the boundaries of political sovereignty, one key aspect of global political justice and an important background condition to the issues of global economic justice treated in the other papers of this volume. I first present an interpretive summary of the traditional arguments against and for intervention, stressing, to a greater extent than is usual, the consequentialist character of the ethics of intervention. It makes a difference whether we think that an intervention will do more good than (...) harm, and some of the factors that determine the outcome are matters of strategy and institutional choice. I then explore the significance of a key factor that makes for much of what is new in the new interventionism: the role of multilateral and particularly U.N. authorization and implementation. I argue that the more salient role of the United Nations should lead us to a more expansive tolerance of international intervention and that global standards of justice, both political and economic, can therefore be more widely enforced against claims to national autonomy. (shrink)