Insomuch as a multipolar world is needed it exists already. It makes sense to encourage emerging countries to engage with specific problems, economic, diplomatic and environmental, and it looks like happening more under Obama. But from there to a kind of international ruling clique, two of whose most powerful members would be one-party states with a controlled press, would be something else.

Do America's critics actively want to see Russia and China pulling more strings in the world, and America fewer? If so those strings could stretch to Western Europe and to Britain itself. Of course, we must welcome the opening doors of China and her entry into ever more international organisations. But as Asia adapts to Beijing's rise, have we reached the stage where we actively want China's autocratic power and influence to grow in the Pacific, and that of our fellow democracy to diminish?

In the Middle East, it may be right to talk more to Iran or Syria, although with all due scepticism and caution. After all, Europe's "wiser-than-thou" diplomacy in the area does not appear to have made a whit of difference to Iran's nuclear development, apart from buying her time for a bit more uranium enrichment. And while our press runs political glamour pieces on President Bashar al-Assad, he remains hand-in-glove with Hizbollah and shows few signs of reforming an odious regime. How safe would you feel in a multipolar world underpinned in the Middle East by a country avid for a nuclear weapon and whose president has religious visions while addressing the United Nations? (I preferred Khrushchev's shoe-banging.) Or by Syria, a Baathist regime style soviétique, with a taste for nuclear adventurism of its own, aided by North Korea?

Then there is the world economy. Currently, America works like a global central bank through the IMF, does most to ensure and protect oil supplies for other countries (for which she is routinely condemned), most to finance the UN and gives a boost to other economies by acting as de facto consumer of last resort. Do we need less of America and more of less reliable nations in these roles too? Vladimir Putin complained at the Davos Forum in January about excessive reliance on the dollar as a reserve currency. That is a point for debate, although one reason the world relies on it so much is that for all its troubles it remains more reliable than the rouble and the renminbi. It helps, for a start, to be convertible.

Putin is not alone, and others in the West make similar complaints. No doubt much of it is part of the ritualised resentment Professor Mandelbaum writes of, addressed for the benefit of domestic audiences to the whipping boy of the world. But the day could come when an America preoccupied with the cost of its own reinvention might weary of the lash. If the world decided it would be better off under the thumb of a sort of untried and undemocratic oligarchy, the feeling in the US might develop that if you think you've got a better hole to go to, with more congenial company, go there. Just don't be surprised if we build up the earthworks around our own hole once you're gone, too high for you to come crawling back.