The United States is today a global superpower without historical precedent. It stands at the centre of an expanding democratic-capitalist world order that is itself, fifty years after its creation, the dominant reality in world politics. Despite expectations that American hegemony would disappear and trigger the emergence of a new and unstable multipolar post-Cold War order, the opposite has in fact happened. American power has grown even greater in the decade since the collapse of the Soviet Union. Although American power is not uniformly welcome around the world, serious ideological challengers or geopolitical balancers are not to be found. Scholars who a decade ago were debating the prospect of co-operation and conflict in a post-hegemonic world are now debating the character and future of world politics within an American unipolar order.