Cosmopolitan justice calls for extensive institutional transformations at the international level. But in the absence of a global enforcing authority, such transformations are bound to be hampered by a range of obstacles, including non-compliance and coordination problems. What solutions can a cosmopolitan thinker offer to address these challenges? In answering this question, the paper focuses on the role that international cooperation between the world?s democracies can play in promoting cosmopolitan aspirations. It argues that such cooperation has a crucial role to (...) play in executing global justice reforms; and furthermore, that the world?s democracies have a moral duty to lead the way in implementing cosmopolitan justice. The paper then suggests that a ?League of Democracies? ? an intergovernmental organization which is open exclusively to the world?s democracies ? could potentially facilitate the type of democratic cooperation that is necessary for cosmopolitan justice. (shrink)