The back-drop to the next president’s foreign policy is the persistent and potentially corrosive debate about US decline.
This has become an academic industry in itself, with books and articles showering from commentators and think-tanks alike.
The bulk seem to take US decline as a given, citing the familiar platitudes of economic sluggishness at home and a rising China boldly marching towards a new Pacific century.
A minority of the commentary takes issue with the whole idea of decline, insisting that for all its problems, the US remains the “city on the hill”: the example which even so many of its detractors want to copy and at the very least – and here the contrast with China is significant – the US remains one of the few countries that has an expansive world role seemingly written into its DNA.
Of course, though, something fundamental has changed.
That proud “uni-polar moment” after the Cold War when the US reigned supreme as the only superpower could not last.