The United States today straddles the stage of global politics without any equal competitor. So the big question is how it will use its great power. Will it turn inwards towards isolationism? Will it accept voluntary constraints by allies, in multilateral arrangements? Will it act globally, but unilaterally, without consultation? Will that unilateral action be self-interested only, or with an eye to giving global leadership?A group of distinguished proponents of these diverse views argue out their differences in this collection of essays. Central issues in their debate are whether isolationism is the same as unilateralism, and the degree to which American political culture feels itself to be part of, or distinct from an emergent global civil society.