FAHRENHEIT 9/11: Documentary or propaganda? Either way, Fahrenheit 9/11 is an incendiary attack on the current resident of the White House, writes Michael Dwyer

Whatever your view of Michael Moore - maverick hero, smooth operator, manipulative opportunist, blatant self-publicist, stand-up comic, salt of the earth, or perhaps a combination of some or all of these - the fact is that many people are taking him very seriously. Very many people, as commentators from the right and left and centre, turn out thousands upon thousands of words pouring scorn, praise and caution on him and his raw, polemical new film, Fahrenheit 9/11.

The film has exercised the media more than any film in years, including this year's other surprise major commercial success, The Passion of the Christ. The acres of coverage, which has extended far beyond the arts and entertainment pages, is far more than most producers could ever dream of achieving with their movies, and certainly not for a documentary with a budget of just $6 million. Fahrenheit 9/11 astonished Hollywood - and Washington - by going to the top of the US box-office on its first week and taking over $60 million by last Sunday, at the end of its second weekend on US release.

Some of this coverage has queried the film's status as a documentary, and Moore's movie certainly will raise troubling questions for anyone naïve enough to believe that the documentary is the purest, most impartial form of film-making. Provocative from start to finish, Fahrenheit 9/11 constitutes a two-hour assault on the presidency of George W. Bush as the clock ticks down to election day on November 2nd. Moore never misses an opportunity to ridicule Bush. His film is deeply biased and brazenly upfront about that.

It begins on US election night in November 2000, questioning the voting system in Florida that secured election for Bush. But the film is principally concerned with the events of September 11th, 2001, and their aftermath. Moore employs sound footage recorded at the World Trade Center on that day and leaves the screen blank for this sequence, before turning to the president's reaction when he hears the news while visiting a junior school in Florida.

Using previously unseen video footage shot by one of the teachers, it shows Bush's blank response as he continues to read a child's book, My Pet Goat, for several minutes. Context is crucial, and it is arguable that a pro-Bush documentary could show the same footage to demonstrate the president's deep state of shock at the terrible news from New York. In that respect, it ought to be noted that much of what else Moore is showing and saying in the film already has been well documented, but it is the selective accumulation and presentation of that data that triggers the power of his film.

Unusually, Moore himself mostly stays off-screen, and this works to the advantage of Fahrenheit 9/11. In the tradition of his earlier work, it is shaped as a potent blending of broad humour and righteous anger, drawing audiences in to be entertained and sending them out thinking about and discussing what they have seen. The film's use of satire rooted in cynicism and indignation is a weapon that has been familiar to radio and television audiences in Ireland and Britain for decades.

This time, however, Moore's emphasis is on anger over humour. He posits his view that an Orwellian climate of fear was fostered in the US after the attacks, allowing for the erosion of civil rights through the introduction of the Patriot Act. The film interviews members of a middle-class peace group in Fresno who learned they had been infiltrated by an anti-terrorism officer only when the officer's death in an accident was reported in the press, and it shows the people of a small Virginia town on an unlikely state of alert.

In footage shot by freeelance crews in Iraq, several soldiers are interviewed and they openly express their disillusionment and despair with the war, and the film features footage of US soldiers ridiculing Iraqi detainees, of Iraqi bombing victims, of US soldiers who returned home mutilated, and of US families embittered with losing their sons in the war and questioning the need for them to be there in the first place.

Fahrenheit 9/11 stands as a rare achievement in agit-prop cinema in that it has progressed far beyond preaching to a converted minority. It has found a very substantial audience and has prompted a level of debate that is healthy for democracy. After all, it could only have been made - and seen - in a democracy.