You know how bad things have got when Jimmy Carter’s critique of your presidency is taken seriously. This week the former US President attacked the current one, saying that, “as far as the adverse impact on the nation around the world”, George Bush’s Administration had been “the worst in history”. It’s one thing to have to listen to Bill and Hillary Clinton claim that things were better when they were in the White House, but Jimmy Carter? Being told by Mr Carter that you’re the worst president in history is like being told by William McGonagall that your poetry stinks.

For the younger reader, perhaps already infused with a nostalgia that recalls the 1970s as a time of peace and prosperity, a brief reminder of the golden era of Carter is in order. It wasn’t all disco and flared trousers and sex without condoms. Also fashionable in those days were unemployment, inflation and communism.

The US jobless rate was more than 10 per cent. Inflation touched 15 per cent. Soviet troops marched unmolested into Afghanistan. America watched helpless as its diplomats were held hostage by Iranian revolutionaries for 444 days. In the rest of the world, from Latin America to Asia, American power yielded to the communist advance; economically, America was being bested by Japan and Germany.

And then there was the moment when the US President was almost felled by a killer rabbit. It struck one day in 1979 when Mr Carter was in the presidential dinghy on a fishing trip in Georgia. A large, evidently amphibious animal with big floppy ears and protuberant teeth swam boldly up to the President’s boat and had to be smacked away with a paddle (a nice metaphor in many respects: the President may have been up the creek but at least he still had his paddle).

Mr Carter’s defenders say: very well. Not our finest hour. But at least people liked us. Better to be pitied than despised. And laugh if you will about killer rabbits, at least Mr Carter’s near-death experience came at the furry paws of an animate creature; Mr Bush’s main brush with mortality in the White House was with a pretzel.

For many Americans, the Carter critique rings true. They wonder whether, finally, this is it for America. Whether two terms of George Bush may have done for the superpower what the Great Depression, fascism, communism and Jimmy Carter failed to do: sow the seeds of its destruction.

The country is in the grip of an unrelieved gloom about its condition. The Iraq war rolls on, sapping self-confidence. In the broader Middle East the war that was supposed to turn history in America’s direction seems to have done the opposite. Iran is emboldened. Syria is throwing its weight around again.

Farther afield, of course, America is despised as never before. Its much-vaunted soft power, the appeal of its freedoms, its lifestyle, its economic opportunities, is tarnished. It is not just Abu Ghraib and Guantanamo, but the very American system itself – its thirst for oil, its healthcare, its inequalities – that is now so readily maligned.

Americans read every day that their economic supremacy is in its last days. This week a delegation from Beijing has been in Washington for economic talks. In the pictures of the event, the Chinese leaders, smiling beneficently on their hosts, looked like nothing so much as a kind of memento mori, a chilling reminder for Americans that the future does not belong to them.

Meanwhile, an immigration debate rages on. Right and Left are furious with a compromise Bill in Congress. The nativist Right, egged on by latterday Goebbelses on TV and radio, thinks America is being overwhelmed by sub-literate Hispanic immigrants, armed with lawnmowers and cleaning brushes, ready to roll in and sweep them away. The bleeding-heart Left thinks that, in allowing an amnesty for only 12 million illegal immigrants, America is inflicting unimaginable cruelties on another 30 million family members who will not be allowed to come into the US.

Steady on. Once Americans get into a funk, there really is no stopping them. It’s an old truth that things are never as good or as bad as they seem and so it is now.

Start with economics. America is not going to be overtaken by China any time in the next century. So large is the US advantage that, even growing at 3 per cent, the country’s economy adds more to the level of global activity than China does growing at 10 per cent.

Its soft power may have been attenuated these past few years, but not destroyed. Who is there to replace America? China? Do me a favour. Does anyone out there really think they would prefer to live in China rather than America? Europe? Viewed from the comforting perspective of a pavement café in Paris, Europe might look a more appealing place. But the continent is in the midst of a long, slow suicide; falling birthrates and a moral surrender to the forces of relativism have left it an easy prey for less tolerant cultures.

There’s no denying that Iraq is a self-inflicted wound and an energy-sapping one at that. But the scale of the damage to America there can be overstated too. All we’ve really learnt in the past five years is that even the US is probably not powerful enough to remake 700 years of history in five years. That doesn’t mean America is weak, just less strong than it thought it was.

Of course, a president, an inept one, can set back the course of a nation’s progress. Like Mr Carter before him, Mr Bush’s ledger is heavy on the liabilities. But America recovered from Mr Carter, thanks to good leadership and the ingenuity of a people whose great gift is their constant capacity to recreate themselves. Who’s betting it won’t do so again?

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