The words used to describe things sometimes tell us less about the thing itself and more about those telling the story: and in the case of the words ‘American Empire’ one could more or less tell in the past that the story was being told by a critic. Not any longer. Indeed, since 9/11 those who have been at the forefront of promoting the idea have not been radical opponents on the left but defenders of the United States on the neo-conservative right. Under conditions where the US dominates the earth like no other power, Empire they argue not only describes what America has become – even though its own leaders invariably fail to recognise the fact; it also indicates to us what has to be done if we are to tackle the threat posed by catastrophic terrorism. And in this the United States now needs to do what it normally does worst: namely learn from the history of other great powers. As one of the new gurus of Empire has suggested, in a world of failed states and terrorist threats, the US has to abandon the idea that it is unique and see how its predecessors, the British and the Romans, created the conditions of order before.