A confident, values-conscious US is the only hope of the West as Europe succumbs to the pressures of Islamisation.

 IN 2003, Tony Blair spoke to the US Congress. "As Britain knows," he said, "all predominant power seems for a time invincible but, in fact, it is transient. The question is: what do you leave behind?"

An excellent question. Today, three of the Group of Seven major world economies are nations of British descent. Of the 20 economies with the highest gross domestic product per capita, no fewer than 11 are current or former realms of Her Britannic Majesty. And if you protest that most of those are pinprick colonial tax havens - Bermuda, the Caymans - okay, eliminate all territories with populations lower than 20 million and the top four is an Anglosphere sweep: the US, Britain, Canada and Australia.

The key regional players in almost every corner of the globe are British-derived - South Africa, India - and, even among the lesser players, as a general rule you're better off for having been exposed to British rule than not: try doing business in Indonesia rather than Malaysia, or Haiti rather than StLucia.

And, of course, the pre-eminent power of the age derives its political character from 18th-century British subjects who took English ideas a little further than the mother country was willing to go. As for the allegedly inevitable superpower of the coming century, if China ever does achieve that status, it will be because the people's republic learned more from British Hong Kong than Hong Kong ever did from the Little Red Book. John Cowperthwaite, the colony's transformative financial secretary in the 1960s, can stake a better claim as the father of modern China than Chairman Mao, and, if Beijing weren't so twitchy about these things, his would be the face they'd plaster over all the banners in Tiananmen Square.

Britain was never an unrivalled colossus, even at its zenith. Yet today, in language, law, politics, business and the wider culture, there is simply nothing comparable in scale or endurance to the Britannic inheritance.

We now live in the American moment. And, even if nobody's planning on leaving, the "what do you leave behind?" question is worth asking. How does the US want to use its moment? What does it wish to bequeath the world?

Even to present the question in those terms feels vaguely un-American. The US has an unmatched dominance that the British never enjoyed and that is historically unprecedented. Yet it remains a paradox: the non-imperial superpower. For good or ill, the American people don't have an imperialist bone in theirbody - as we saw, in fact, in post-liberation Iraq.

A week before the President's inaugural address in January 2005, I picked up the Village Voice for the first time in years. Couldn't resist the cover story: "The Eve of Destruction: George W. Bush's Four-Year Plan to Wreck the World."

If only. It's so easy to raise expectations at the beginning of a new presidential term. In the wake of September 11, the administration pledged itself to a long-overdue reversal of decades of misguided foreign policy that the second inaugural address made explicit: Bush committed the US to spreading freedom through the Muslim world - or, as a sceptical friend of mine phrased it, we're going to shove liberty down their throats whether they want it or not. It was presented as a kind of lo-carb, organic, environmentally friendly version of "the white man's burden".

But no country has ever seemed more burdened by it. It's America's world; it just doesn't want to live in it. Almost as soon as US troops entered Iraq, senate Democrats demanded to know what the "exit strategy" was. "Exit strategy" is a phrase that might have been designed as a textbook definition of a lack of will. In war, there are usually only two exit strategies: victory or defeat.

"Europe and America," said Bush in Ireland in 2004, "are linked by the ties of family, friendship, and common struggle and common values." If so, the US president and many other Americans have an all too common struggle articulating what those common values are. In Prague in 2002, Bush told fellow NATO members: "We share common values, the common values of freedom, human rights and democracy." Big deal. In a post-communist world, these arevague, unobjectionable generalities toeveryone except the head hackers in the Sunni Triangle.

The "common values" stuff is the transnational equivalent of "have a nice day". It's when you try to flesh it out that it all gets more complicated. The US spends 3.4 per cent of GDP on defence, the other NATO members spend on average 1.9 per cent. So, if they do share "common values", Europe's prepared to spend a lot less defending them.

On a raft of other issues, from guns to religion, the US is also the exception. In North American terms, it's Canadian ideas, from socialised health care to confiscatory taxation, that are now the norm in the other Western democracies and, alas, in many of the emerging democracies.

The raucousness of American pop culture - jazz, showgirls, hardboiled cops - belies the hyperpower's geopolitical circumspection. And, on the receiving end, the Americanisation of global pop culture puts a greater premium on being un-American in every other respect. Almost all the supranational bodies - from the EU to the International Criminal Court - are, if not explicitly hostile to American values, at the very least antipathetic to them. In the face of this rejection ofthe broader American culture, the popularity of Brad Pitt and Angelina Jolie isn't muchconsolation.

Britain exported its language, law and institutions around the world to the point where today there are dozens of countries whose political and legal cultures derive principally from London. On islands from the Caribbean to the South Pacific, you can find miniature Westminsters proudly displaying their maces and Hansards. But if England is the mother of parliaments, the US's is a wealthy spinster with no urge to start dating. Of all the new nations that have come to independence since 1945, not one has adopted the American system of republican decentralised federalism - even though it's arguably the most successful ever invented.

The US has zero interest in empire, for obvious reasons. For one thing, it's already as big as an empire, and most countries that controlled that big a land mass would probably run it in imperial fashion.

Instead, the US took a federation designed for a baker's dozen of ethnically homogeneous east coast colonies and successively applied it across the continent and halfway over the Pacific. It's not strictly true that the sun never sets on the American Republic, but it's up an awful lot of the time.

Beyond that, Americans are deeply suspicious of the notion that you can swan around the world "giving" freedom to people. They have to want it, like the first Americans did - as we say in New Hampshire, live free or die. If the Iraqis want a free society badly enough,they'll stick with it; if they don't andthey take the easy option of falling for some puffed-up strongman, that's their problem, not America's.

While this might be philosophically admirable, the practical drawback is that power abhors a vacuum. If the US won't export its values - self-reliance, decentralisation - others will export theirs. In the '80s, US historian Paul Kennedy warned the US of "imperial overstretch". But the danger right now is of imperial understretch - of a hyperpower reluctant to sell its indisputably successful inheritance to the rest of the world.

After Mao's victory, America's anti-communists famously demanded to know: "Who lost China?" Answer: Nobody. China wasn't lost. Chiang Kai-shek had never won it in the first place. He was merely an early beneficiary of US foreign policy's faith in unreal realpolitik - the system embodied in the cynical line that so-and-so may be a sonofabitch but he's our sonofabitch.

In the case of Egypt's Hosni Mubarak, the House of Saud, and many others, the obverse is more to the point: he may be our sonofabitch but in the end he's a sonofabitch. Even if it wasn't licensing anti-Americanism as a safety valve for what might otherwise be more locally directed grievances, the Cairo government would not be a meaningful friend. There's a huge difference between having a regime as an ally and having a nation as one, the difference being Egypt's Mohammed Atta and 15 Saudi citizens flying through the windows of the World Trade Centre and the Pentagon, which suggests considerable limitations to the theory that, as long as the US gets along fine with President Mubarak and key Saudi princes, it doesn't matter if everyone else in Egypt and Saudi Arabia is shouting, "Death to the Great Satan!"

So instead of waiting 10 years and demanding to know, "Who lost Japan? Who lost Russia? And Europe? Oh, and who lost Britain?", analysts might be better advised to ponder why a supposed moment of unprecedented unipolar dominance doesn't feel like it. Most Americans are familiar with their stereotype abroad: loud, brash, ignorant, arrogant. It is, in most respects, the inversion of reality: America maybe the most modest and retiring hegemon in history.

"You're either with us or you're with the terrorists?" Most of America's European "allies" checked the Neither of the Above box and most Middle Eastern "allies" checked the Both of the Above box. Belgium isn't exactly with the terrorists but it isn't with us in any meaningful sense. Saudi Arabia is with us but also funding terrorists in every corner of the world. And both countries get away with it.

The US has huge advantages. On the continent, the Euroconsensus is shrinking both its economy and its population; the US is managing to grow both. Why then project US power through transnational institutions disproportionately in thrall to European ideas?

There's something a little bizarre about a so-called unipolar world in which it's the unipole that gets shafted every time. Russia and China have already determined that, whatever their own little local difficulties with Muslims, their long-term strategic interest lies in keeping the jihad as a US problem. The internal logic of the demographic shifts due to higher birth rates for Muslims compared with non-Muslims such as Europeans will be to make much of the world figure it makes sense to be on the side America's not.

Al-Qa'ida thinks it's got America pegged - an effete, fleshy sultan sprawled languorously on overstuffed cushions, lost in sensual distractions. The choice for the US is between those who believe America can take the lead in shaping the times and those who think the most powerful nation in history can simply climb in the Suburban and go to the mall for its entire period of dominance. That's what the great Democratic Party all-purpose "multilateral" cure-all for US foreign policy boils down to: "We need to hand power back to the UN. Or the EU. Or the Arab League. Or the Deputy Fisheries Minister of the Turks and Caicos Islands." Or as Thomas Friedman, the hilariously tortured foreign policy grandee of The New York Times, agonised: "Mr Bush needs to invite to Camp David the five permanent members of the UN Security Council, the heads of both NATO and the UN, and the leaders of Egypt, Jordan, Saudi Arabia and Syria. There, he needs to eat crow, apologise for his mistakes," etc, etc.

Why would it be in America's interest to inflate the prestige of Boy Assad and Mubarak? This lame-o multilateral outsourcing is the geopolitical equivalent of subcontracting your lawn care to undocumented immigrants: here you are, we don't mind giving you the money, just take care of it, we don't want to know the details, we want to go back to watching American Idol. Is foreign policy justanother one of those "jobs Americans won't do"?

Common values and universal values are not all that common and universal, and the willingness to defend those values is even rarer. They've been sustained over the long haul by a very small group of countries. In the years ahead, the US has to take the American moment seriously - in part, to ensure that the allies of tomorrow don't make the mistakes Western Europe did. That means, at the very minimum, something beyond cheeseburger imperialism. In the end, the world can do without American rap and American cheeseburgers. American ideas on individual liberty, federalism, capitalism, and freedom of speech would be far more helpful.

In 2004, Goh Chok Tong, then prime minister of Singapore and a man who talks a lot more sense than most continental prime ministers, visited Washington at the height of the Democrats' headless-chicken quagmire frenzy. He put it in a nutshell: "The key issue is no longer WMD or even the role of the UN. The central issue is America's credibility and will to prevail." The prime minister of Singapore apparently understands that more clearly than many Americans.

Edited extract from America Alone: The End of the World as We Know It, by Mark Steyn, published by Regnery Publishing and distributed by DA Information Services, $49.95.

www.marksteyn.com