In this paper we explore the sustained and multifaceted attempt of Jürgen Habermas to reconstruct Kant's theory of cosmopolitan right for our own times. In a series of articles written in the post-1989 period, Habermas has argued that the challenge posed both by the catastrophes of the twentieth century, and by social forces of globalization, has given new impetus to the idea of cosmopolitan justice that Kant first expressed. He recognizes that today we cannot simply repeat Kant's eighteenth-century vision: that if we are to grapple with the complexities of present-day problems, it is necessary to iron out certain inconsistencies in Kant's thinking, radicalize it where its break from the old order of nation-states is incomplete, socialize it so as to draw out the connections between perpetual peace and social justice, and modernize it so as to comprehend the “differences both in global situation and conceptual framework that now separate us from him.” 1 His basic intuition, however, is that Kant's idea of cosmopolitan right is as relevant to our times as it was to Kant's own. If it was Kant's achievement to formulate the idea of cosmopolitanism in a modern philosophical form, Habermas takes up the challenge posed by Karl-Otto Apel: to “think with Kant against Kant” in reconstructing this idea. What follows is a critical assessment of Habermas's response to this challenge. We focus here on the dilemmas he faces in grounding his normative commitment to cosmopolitan politics and in reconciling his cosmopolitanism with the national framework in which he developed his ideas of constitutional patriotism and deliberative democracy.