Hollywood seems to have joined the ranks of those who badly miscalculated their reaction to 11 September. Greg Killday at the Hollywood Reporter spoke for the conventional wisdom that had swept LA well before the twin towers crumbled: "There are indications that, in the wake of the tragedy, the film industry might begin to reassess its dependence on its ever-escalating images of destruction." Arnold Schwarzenegger's huge action blockbuster Collateral Damage, in which he takes on terrorists who destroy a skyscraper, was indefinitely postponed. Bloodthirsty action movies were flushed out of the pipeline, even those quite far on in the production process. One Hollywood executive said that next year's film output would be "like a series of Little House on the Prairie".

Big mistake. While Hollywood was moving into soft-and-cuddly mode, Americans were flocking to their video stores to rent - according to Blockbuster charts - terrorist-themed films by the basketload. Stores ran out of copies of The Siege, Air Force One (in which the president's plane is hijacked by Arab terrorists) and Independence Day (in which the White House and the NewYork skyline are destroyed by aliens). A surprised Blockbuster manager said there was "an unusually high interest in action movies dealing with themes closely tied to the events of the week. They wanted . . . anything where terrorists got the stuffing kicked out of them."

Films shaped public discourse following the attacks. It swiftly became a mind-numbing platitude that the attack was "just like a movie". A witness, who was standing near the towers when the planes struck (and who fled only after the first tower collapsed), said: "I just felt safe. It was a movie set and I was an extra, so nothing could hurt me." Thus people turned to movies to complete the narrative arc. It was going to take (at best) months to get any kind of revenge against Osama Bin Laden, so Americans turned to the quick-fix comfort of a film where the bad guys are certain to be punished, preferably in a horrific way.

One Hollywood player was astute enough to realise this. Sylvester Stallone has never had any acting ability. He has made himself a multimillionaire by cleverly choosing projects that coincide with the public mood in the US. He is, as you read this, reportedly holed up in his California mansion working on Rambo IV, in which Rambo "goes into Afghanistan and whoops the Taliban's ass".

The American understanding of the outside world is dominated by cinema images. President George W Bush's plan for a national missile defence is named after one film (Star Wars) and is based on an idea Ronald Reagan got from a movie in which he starred as a youth. That Americans should return to the iconic image of Rambo at this moment is predictable. By rewatching the Rambo trilogy, it is possible to trace the American right wing's understanding of the vast, cloudy non-America that it glimpses only occasionally.

First Blood, the 1982 original Rambo film, is the story of a disturbed former Green Beret (Stallone/Rambo) who, unable to cope in civilian life, is pointlessly victimised by the police for "vagrancy". Here, Rambo represents an America that cannot acclimatise to the post-Vietnam world. He cannot see the world without flashbacks to the carnage in Vietnam. For him, "nothing is over . . . I come back to the world [Vietnam is, it seems, literally another planet] and I see all those maggots at the airport protesting me, spitting, calling me 'baby killer' . . . Who are they to protest me?" The rest of the world is viewed with a casual hatred second only to the contempt for the supposed "liberal elite".

Rambo: First Blood Part II was made in 1985, when Reagan's second presidential election victory had emboldened Americans and their film-makers to be more openly belligerent. Rambo is released from prison on the condition that he goes on one final mission: back to the jungles of Nam to rescue POWs still trapped there. He asks his commander: "Sir, do we get to win this time?" "That's up to you, Rambo." A liberal politician tries to cover up the evidence Rambo discovers of living prisoners, and asks: "What do you want to do? Start the war again? Bomb Hanoi?" The film-makers' answer, clearly, is "yes".

Rambo III is extraordinarily revealing about the propaganda role played by these films. The places to which Rambo is sent - Peshawar, Kabul - have become very familiar in the past few months. Rambo is told that the Soviets are "wiping out a race of people" and - echoing the First World War propaganda about "the Hun" - that "pregnant women were killed with bayonets and their babies were thrown into the fire". The mujahedin, whose ranks at this time would have included Bin Laden, are heroic, brave and true. The movie ends with the words: "This film is dedicated to the gallant people of Afghanistan."

It will be fascinating to see how the new Rambo movie deals with this. Will his former gallant comrades (including the doe-eyed innocent child who tries to rescue Rambo and pleads with him to take him back to the "land of the free") now be wicked, slitty-eyed villains? This exposes the contortions that US propaganda has to pull off. The world must be neatly divided between the purely good Nietzschean superman and the purely evil pantomime villain. There can be no moral ambiguity - "If you aren't with us, you're against us," as President Bush said. The American right wing is trying to craft an America in Rambo's image. Hollywood must provide alternative popular narratives. It can't run away from the war on terrorism, as Hollywood bosses thought at first. But must they simplistically reinforce it?