The Assassination of Jesse James by the Coward Robert Ford (15)

Robert Ford was a young member of Jesse James's last gang: in 1882, he shot his mentor dead, while the outlaw had his back turned to dust a picture. Only one of their names lived in posterity, but in The Assassination of Jesse James by the Coward Robert Ford, it's Ford who steps forward to take his place as the true subject of this extraordinary epic ballad of a film.

Adapted by writer-director Andrew Dominik from Ron Hansen's novel, this is a strange, haunting work. Very much an American art movie, a poetic Western in the grand style, it bears traces of Sam Peckinpah and John Ford, but is closer to Terrence Malick in the way it dwells on nature, on the seasons and the sweep of the American landscape, as much as it does on the actions of people. The figure in the foreground, played by Brad Pitt, is one of the leading deities of the Wild West outlaw pantheon, but the story is about what happens when a bandit's career is over. There's only one piece of outright derring-do in the film, the James Gang's final sortie, a Missouri train robbery in 1881. It starts as chilly son et lumire, with lantern-bearing figures looming among trees at night, then turns into a piece of tawdry, brutish business, in which Jesse reveals himself as a vicious sociopath rather than the Robin Hood of legend.

Afterwards, Jesse's older brother Frank (a leathery, saturnine Sam Shepard) retires and Jesse goes home to his wife (a nearly silent Mary-Louise Parker, whose part seems to have nearly vanished in the final cut) and a sort of citified respectability. The gang members disperse to plot, bicker and live in fear of a visit from Jesse, an increasingly paranoid figure simmering in his "depressions and derangements", as the voice-over puts it.

Among the gang is Bob Ford (Casey Affleck), a gauche 19-year-old who idolises Jesse, treasures a stash of penny-dreadfuls about him, and dreams of a great destiny which we know from the start lies ahead, after a fashion. Bob is well aware, though, that he's hampered by "the shabby first impression I make": people naturally seem to get up and walk away when this eagerly grinning puppy appears, as if they already know the baleful part that he'll play. Jesse himself seems to twig that there's a sort of John Lennon-Mark Chapman dynamic brewing between him and his shy fan: "You want to be like me," he asks Bob, "or you want to be me?".

Casey Affleck has been a background player for so long a mere scenery-shifter in the Ocean's Eleven films that his emergence as a lead here is nothing short of revelatory. His piping voice and oddly childlike face make it clear why everyone finds Bob such an irritation. Yet Affleck's achievement is to make Bob not only knowable, but even oddly likeable, making us understand why Jesse likes having him around.

Robert Ford was an eternal also-ran, one of history's supporting players which makes it ironic that it was Brad Pitt who won this year's Best Actor award in Venice rather than Affleck, whose show this really is. Nonetheless, Pitt is outstanding as a monster of tarnished charisma, a brutish hood whose bonhomie is skin-deep, whose eyes in a face that here looks heavy, coarsely handsome bespeak perpetual fear. The film plays on our notions of bravery and cowardice in a violent world: Ford may shoot Jesse in the back, but it's no less than Jesse does to one of his own men. When Bob turns against his idol, it's betrayal on a large, complex scale that of a Judas, rather than a mere turncoat.

This is the second film from Andrew Dominik, whose debut Chopper was impressive, but hardly suggested that he had anything this visionary in him. The Assassination of Jesse James commandingly renews the tradition of vastness in the Western. Seeing Roger Deakins's photography, you feel that you're really looking into the past, but into a time when the past was new: the finer details bring out the rawness of timber floors, the brightness of dust motes in sun in a newly abandoned house.

Among the supporting cast, there are terrific performances from Sam Rockwell as Bob's doomed brother Charles, and from Paul Schneider as a slyly libidinous gang member ("I'm what they call an inamoratoo"). This is also one of those rare films that manage to be persuasively literary. Hugh Ross's voice-over narration maintains the tenor of Hansen's prose, mixing Melvillean archaism with a sober air of documentary reportage, heightening the sense of inevitability.

That inevitability comes to the fore in an extraordinary coda. After James's death, the Ford brothers make a career from re-enacting the killing on stage: Bob briefly becomes a celebrity, America's first "reality show" fly-by-night success. For this is a story about fame and adulation and their deranging effects. Bob ends up the subject of a contemptuous ballad "Robert Ford, that dirty little coward" which Nick Cave sings in a pithy bar-room cameo. Cave and Warren Ellis also contribute a magnificent brooding score, Ellis's funereal violin setting a tone of solemn inexorability.

My only misgiving is a certain self-consciousness to the film's magnificence. Dominik sometimes pursues poetry a touch deliberately sequences often beginning with the edges of the frame blurred, as if in a snow globe and the whole thing comes across as a little earnestly determined to be a Great American Movie. But that is what it may very well be: this is certainly a film of beauty, intelligence and ferocity, an exercise in the American sublime that has its roots in the bitter, brutal real.

Need to know

JESSE WOODSON JAMES was born in 1847 in Clay County, Missouri, but his death 34 years later has long been disputed. Some believe James survived Bob Ford's treachery and lived in Guthrie, Oklahoma, as late as 1948. A man named J. Frank Dalton, who claimed to be James, died in Granbury, Texas, in 1951 aged 103. Some claim the true recipient of Ford's bullet was Charles Bigelow, reported to have been living with James's wife at the time. James's 'body' was exhumed in 1995, and DNA tests suggested it was indeed him.

Further reading 'The Assassination of Jesse James by the Coward Robert Ford' by Ron Hansen (Souvenir Press price 8.99)