But the days of American hyperpower seem to have morphed into the days of American impotence. Those who longed for America's power to be checked should beware of what they wished for. With revolutions shaking the Middle East, America will at most "lead from behind", code for the abdication of America's leadership even at the price of inaction. When Sudan launches another round of its war of extermination against its largely defenceless neighbour, South Sudan, America will not even supply anti-aircraft guns, to say nothing of some rhetorical succour, which costs little. After nearly 16 months of ferocious government repression in Syria, America is behind — and not even leading — the ineffectual international efforts to solve the crisis. The result is horrific civilian casualties and the very possible survival of the Syrian regime which is inflicting them. In both cases, America's eclipse is counterbalanced by the rise of new powers who fill the void. They are not as benign.

This is the meaning of putting a check on the hyperpower, and the world of 2012 looks infinitely more dangerous as a consequence of declining expectations that America will intervene to solve crises.

In the past, America's military umbrella did not always open to protect struggling nations at the four corners of the earth. America did not always intervene; even when it did it sometimes happened late in the game and it was not always the best course of action. But it often made the difference. Its rhetoric of freedom offered hope to those under the boot of tyrants. And its record gave the impression that America might act on its words. Besides, the knowledge that America's aircraft carriers might be around the corner gave pause to those wishing ill upon its allies and friends.

That is no longer the case. America has disengaged. Its president seems to have bought Védrine's argument. And with that, America's competitors will gladly take its place. Their contempt for America is worse than their fear, because unlike their fear it feeds on America's weakness. They will reshape the world in their own image, unless America stops them.

A world at peace needs an American gendarme. The US's temporary retreat has left a sense that troubles will now fester and solutions may turn out to be worse than the problems — think of Russia bailing out Greece, Bashar al-Assad remaining in power in Syria, or Iran getting nuclear weapons. It is not a pretty picture.

And probably not one that even Hubert Védrine would subscribe to today.