The goal of this dissertation is to defend the Kantian cosmopolitan ideal in the context of contemporary debate about global ethics. Kant's cosmopolitanism has been criticized for its sharp dualism between morality and legality, which deprives it of the very potential for a practical project toward perpetual peace that it promises. This line of objection, famously raised by Hegel, enables a competing conception of cosmopolitanism. Although Hegel's situated or rooted conception of self and state provides us with relevant resources, Kant's ideal cannot or should not be replaced by Hegelian principles. An adequate appropriation of Kant's espousal of cosmopolitan rights that has been modified to accommodate Hegelian insights ought to endorse global efforts to economically and politically empower vulnerable global citizens in our time. At the end of the 20th century, John Rawls drew a sharp distinction between domestic and global justice under the banner of "realistic utopianism." However, a form of cosmopolitan vision seems inevitable even to correct forms of profound domestic injustice. Drawing on Amartya Sen's work, this dissertation instead examines a conception of development that may eschew charges of metaphysical as well as political imperialism. A defense of Kantian cosmopolitan principles requires, in turn, a closer examination of a so-called chasm between moral universalism and political inegalitarianism implied in Kant's work. Revisiting recent debates on Kant's racism invites us to think that a cosmopolitan responsibility suggests not only the need to ensure formal rights of global others, but also the urgency to nurture our emotions toward these others. In short, the moderate cosmopolitanism that this dissertation endorses as the most suitable principle of global ethics has a Kantian face with a Humean heart across and inside borders.