  It is often argued that it is impossible to change the current system of states and to form a world–state or a global federation of states. This claim is hard to maintain, however, in the face of the existence of the United Nations, the existence of states with more than a billion people of heterogeneous backgrounds, and the experience with the United States and the European Union. So in order to be taken seriously, the objection must instead be that it is impossible to form a good state or federation of that magnitude, i.e., that it is impossible to realize or even approximate the cosmopolitan ideal in a way that makes it worth pursuing and that does not carry prohibitive risks. Here political cosmopolitans disagree among themselves. On one end of the spectrum we find those who argue in favor of a strong world-state, on the other end we find the defenders of a loose and voluntary federation, or a different system altogether.