But people should be careful what they wish for. A domestic nationalist backlash against the policies that led to the war is brewing, with implications for how the US will deal with Europe and the rest of the world down the road. Like it or not, American power and involvement are necessary to the proper functioning of world order, and the kind of role that a post-Iraq United States may play is very much up for grabs.

Two recent events constitute straws in the wind. After the protests and embassy-burnings over the Danish cartoons, no major US newspaper was willing to publish the cartoons, and most editorialists took a holier-thanthou attitude to those European papers that did. While one might question the prudence of publishing the cartoons, the violent reaction was a clear case of intimidation, in many cases officially sanctioned, and few Americans criticised the protests or stood up for the right of free speech. Many seemed to feel a certain satisfaction that this time Europeans rather than Americans were feeling Muslim wrath.

The second, and more egregious, case was the successful blocking by the US Congress of the purchase by Dubai Ports World of a British company that operates six US ports. Coming at a time of heightened economic nationalism on the part of countries such as France, Spain and Poland, which have recently sought to prevent such takeovers, this shameless pandering to public fears of terrorism undermined every principle of openness and globalisation that the US has been preaching in recent years.

What was most notable, however, was the identity of some of the panderers. While many rightly blamed George Bush for creating a general fear of Arabs and terrorism, Democrats were among the loudest critics, in particular Charles Schumer and Hillary Clinton, the Democrats' leading candidate for president in 2008. Clinton, who has positioned herself to the right on security issues, saw an opening to attack the president and argued that the Dubai takeover would constitute a violation of US sovereignty. It seems not to have occurred to her that by this logic American multinationals are violating the sovereignty of virtually every country on the planet.

Schumer, Clinton's fellow New York senator and liberal torchbearer, has been leading the charge against outsourcing and competition from China and India. He has been pressing relentlessly for sanctions against China for not revaluing the yuan and for a host of what he labels unfair trade practices. While the world has focused on Iraq, trade and jobs remain the most important international issues to many US voters, and Schumer and other Democrats are ready to respond with a protectionist agenda.

We have, then, the makings of a perfect storm. Bush's red-state conservative base tends towards a pugnacious nationalism that opposed humanitarian intervention during the Clinton years. These voters were mobilised by September 11 to support two wars in short order; while they remain loyal to the president, perceived failure in Iraq will turn them in a more openly isolationist direction. Democratic voters, meanwhile, have been moving in an economically nationalist direction and are gearing up for a big fight with America's leading trading partners in Asia. Voters in both parties have become more sympathetic to calls for closing America's borders and reducing immigration. Many in Europe are eagerly awaiting the end of the Bush years, but it is not clear that a Democratic administration will be more broadmindedly internationalist.

By invading Iraq, the Bush administration allowed what should have been characterised as a fight with a narrow extremist ideology to escalate into something the Islamists could claim was a clash of civilisations. But that clash will play itself out in large measure in Europe, the breeding ground for Mohammed Atta, Mohammed Bouyeri and the July 7 bombers. The controversy over the cartoons underlines the fact that the US and Europe have more in common in the struggle with radical Islamism than either side would like to admit. Cooperation to prevent this escalating into a broader civilisational struggle, and to maintain a generally open, integrated international order, will require solidarity. Neither European indulgence in feelgood anti-Americanism nor a bipartisan rise in US nationalism and populism brought about by perceived failure in Iraq will help.

· Francis Fukuyama's latest book, Neocons: America at the Crossroads, is published this week by Profile Books; to order a copy for £11.99 with free UK p&p (rrp £12.99) call 0870 836 0875 or go to theguardian.com/bookshop

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