On both theoretical and analytic accounts, cosmopolitanism and realism seem destined to bypass each other, one entering, at best, the normative dimension of social science, the other, stressing its positive dimension. In this article, I want to suggest that this opposition needs to be unsettled for future theorization and (perhaps) practice of world politics. Taking these two schools of thought is exemplary since their respective theoretical modalities and tenets seem so far opposed. Arguing for convergence between them constitutes part of an emerging attempt, on the part of political philosophers, theorists and international relations scholars today, to recast the conceptual landscape of international relations in response to present complexities of political agency. This convergence is here situated in terms of: (1) the legitimacy of power; (2) the increasing immanence of justice to power in an interdependent world; and (3) the importance of moral leadership in the world political domain. The article is theoretical in modality and diction; outstanding empirical questions are posed once these points are made.