In the realm of international relations put-downs, none can touch Dean Acheson's description of Britain in the 1950s as a country that had lost an empire but not yet found a role. It's a jibe that has always rankled the British, particularly since Acheson's America did more than any other country to hasten the end of the British Empire – and then to quietly take up the reins of a world order the British had done so much to build.

The British have since developed a range of coping strategies for their loss of empire. One early gambit was to try to tell the Americans how to run their imperium. In Harold Macmillan's view, the Americans were a twentieth century version of the brash, brutal Roman Empire to which the British could play the role of the wise, cultured Greek advisers.

More recently, the British coping strategy has been to forecast the end of the American empire. This began with Paul Kennedy's prediction of American imperial overstretch in the 1980s. More recently Niall Ferguson has pronounced that it's all over, while Gideon Rachman tells the readers of Foreign Policy why China is the imperial challenger America had to have.

The curious thing is that Americans appear to love forecasts of their decline spoken with an Oxbridge accent. Kennedy, Ferguson and Rachman have been eagerly embraced by the Ivy League, and are high profile commentators in the US (despite being frequently wrong in their forecasts).

It makes one wonder whether the ultimate coping strategy for loss of Empire is to watch the next one fall. And should Kennedy, Ferguson and Rachman be right about America's decline, what will Americans' future coping strategies be?