Brad is the hero for our time. Flawed

Hollywood has a new hero, his torso rock-hard and rippling with muscle. He, or rather the film he stars in, cost $175m (£104m) and required the presence of 1,000 Mexican extras, as well as 250 Bulgarians from a sports academy in Sofia. The movie is based on the Illiad, with bits of the Odyssey thrown in, and is a departure for Hollywood studios, which have traditionally located their epics - Spartacus, Quo Vadis, Antony and Cleopatra, Gladiator - in ancient Rome rather than Greece. Its key figure is Brad Pitt as Achilles, greatest warrior among the Greek army besieging Troy. Pitt offers American audiences a model of valour and sacrifice at this most difficult moment in their history.

"Today, when our politicians are so grey, so bland, we need reminding of what it is to have moral truth, higher ideals," says Troy's German director, Wolfgang Petersen. It's not difficult to imagine Hollywood studio bosses seizing on Homer's tale of a group of countries (actually city-states) banding together to punish a wrong done to one of their number, in an early version of Nato's article five, the collective defence clause. The parallel (to which Pitt himself has alluded) is all the more insistent when you recall that Troy was in Turkey, which shares a border with present-day Iraq. In the film it is Western leaders who prevail, although they have to endure a siege lasting 10 years.

I don't know whether Donald Rumsfeld has a Trojan horse up his sleeve, but this is the kind of myth-making Americans love. All countries have fantasies about themselves, but few display them so confidently as the United States. They began to emerge with the founding of the nation, when its leaders modelled their political system on Republican Rome; George Washington was often portrayed in a toga, overlooking the fact that the high-minded Republic degenerated into a brutal, corrupt empire. That is how many foreigners regard the US today, especially in the Middle East, where the invasion of Iraq is viewed as a neo-imperial adventure designed to further American power and interests.

The unfairness of that verdict irritates many Americans, but the rhetoric of the country's leaders must bear a great deal of the blame. Earlier this month, when pictures of torture began to emerge from Abu Ghraib prison in Baghdad, politicians and generals united in declaring such behaviour was not "the American way". They were expressing the widely held belief that the US stands for democracy and freedom, yet only last week Rumsfeld told a Senate hearing that Pentagon lawyers had approved sleep deprivation, dietary changes - presumably a polite description for starving captives - and other methods used to break prisoners.

America's friendly critics would welcome evidence of contestation and debate in a nation that too often appears to give unquestioning assent to its own myths. Most Americans believe their country is a force for good and are shocked by evidence to the contrary, whether it comes in the form of support for military coups in Latin America or mistreatment of prisoners in Guantanamo Bay. As shaken Senators emerged last week from viewing more horrific pictures from Iraq, I couldn't help recalling that one of the first acts of the Bush administration was to overturn Bill Clinton's decision to sign the statutes of the International Criminal Court. The incoming president wanted nothing to do with the court, and I suggested at the time that US governments had good reason to fear a tribunal with jurisdiction over war crimes, such as the massacre at My Lai in Vietnam.

There also seems to be collective amnesia in the US about a spate of articles and TV programmes that suggested, in the months after 11 September 2001, that torture might be justified in some circumstances. Given the lies the Bush administration told about links between the suicide bombings on the East Coast and Iraq, it seems likely that some of the soldiers and military police at Abu Ghraib believed they had encountered just those circumstances. Now, as the world contemplates the Bush administration's shame and its lame excuses, a Hollywood star turns up at the local multiplex, streaked with blood and sweat, to make ordinary Americans feel good again. Anyone familiar with the Illiad might conclude that Achilles, the warrior with a fatal flaw, is a more appropriate image for contemporary America than Hollywood realises.