But that would be to forget that, as the current crisis warps political sanity, we may be entering a phase where rationality could follow the global economy into recession.

For a sane view of the USA you have to look to Americans themselves, just as you look to them for the best science, the best orchestras, novelists, architects, art historians and (so I am told) classicists. The clearest statement of the facts about the US, its enemies and critics, is by Michael Mandelbaum, a foreign policy professor at Johns Hopkins University esteemed for the steely precision of his analyses.

Why is it, he asks in The Case for Goliath, that whereas states as strong as the US are historically subject to alliances to check them, no such anti-American alliance has formed or shows any sign of forming today? "The explanation for this gap is twofold. First, the charges most frequently levelled at America are false...second, far from menacing the rest of the world [the US] plays a uniquely positive global role. The governments of most other countries understand this, though they have powerful reasons not to say so explicitly."

There follows a highly contemporary message: that America's willingness to pursue the international activism we publicly deplore and privately welcome depends not so much on the rise of China but on the demands of Medicare and the social security budget. Three things about the US global involvement, he writes, may be safely predicted: that other countries "will not pay for it; they will continue to criticise it; and they will miss it when it is gone".

How keen are we in practice to dilute and redistribute US power? If it is to be a multipolar world, who, beyond Europe, would form these poles? India, Japan, Russia, China, the Middle East, South America, presumably. But you cannot line up countries or regions as candidates for a global oligarchy by virtue of their future power or influence.

How stable are the last four of these countries and regions, and how democratic, mature, honest or corrupted are their societies? If they are to form the underpinnings of a new international order, slipped into place deftly so as not to bring everything down as America withdraws, we need to know how much weight they can bear, as well as how they might bear down on us.