What follows is an attempt to acknowledge the complexity and relevance of debates about the relation between legality and legitimacy as it bears on political behaviour. The opening section is intended to orient these international policy debates in wider traditions of political theory, particularly as they bear on the nature of sovereignty and the state. On this basis, the two prominent, recent instances of controversial recourse to war (Kosovo and Iraq) are considered from the perspective of legality and legitimacy, first as a matter of juridical evaluation and then from the perspective of international reputation. The focus throughout reflects a concern with the qualities of American global leadership since September 11th, and how this leadership should or should not be guided by canons of legality.