Exiles have long been transformative actors in their homelands: they foment revolution, sustain dissent, and work to create renewed political institutions and identities back home. Ongoing waves of migration ensure that they will continue to play these vital roles. Rather than focus on what exiles mean for the countries they enter, a focus that often treats them as passive victims, The Ethics of Exile: a political theory of diaspora recognizes their political and moral agency and explores the rich and vital relationship to the communities they have left. I argue that exile politics performs two functions: it can correct defective political institutions back home, and it can counter asymmetries of voice and power abroad. In short, exiles can act both as a linchpin and a buffer between political communities in crisis and the international actors who seek to, variously, aid and exploit them.