There's a long and, on the whole, honorable tradition in films of what you might call the circular story, in which everyone exists to serve a portion of a plot that ultimately comes back upon itself to complete the circle. It can be witty ("Dinner at Eight") or ironic ("La Ronde") or, as in "Crash," tragic. In each case we meet people who exist only to prove a point, you might say. They have no lives outside of the scriptwriter's plan for them; they're used and then thrown away.

"Crash" is the directing debut of Paul Haggis, who wrote "Million Dollar Baby," and he has story and cowriting credit here. It begins on a rare snowy night in Los Angeles when the car of LAPD detective Graham (Don Cheadle) and his partner/girlfriend Ria (Jennifer Esposito) is rear-ended and Ria and the Asian driver of the other car have at each other with racist taunts. It then cuts back to the day before, when we see the first of what will be a series of vignettes each containing a moment - or a lifetime - of racist actions. No one is exempt: the good are bad, the bad are good but mistaken; everyone has a story that is the same story.

A racist cop (Matt Dillon) taunts a black couple, Cameron and Christine, with a humiliating traffic stop, an action that mortifies his young partner (Ryan Phillippe) and precipitates another humiliating fight between the couple (Terrance Howard and Thandie Newton). Cameron is a successful television director who then must bow to his producer who makes him reshoot a scene because a character isn't 'black' enough. Two young black men (Ludacris and Chris Bridges) deplore racism and then carjack the Lincoln Navigator of a white couple (Brendan Fraser and Sandra Bullock). Bullock in turn is the racist employer of a Latina maid; Fraser is the District Attorney who doesn't want to lose the black vote.

On and on it goes. The bad Dillon turns out to be consumed with love and concern for his sick father, and then makes a heroic rescue - an homage to "The Princess and the Warrior" - of the very woman he humiliated. The Iranian proprietor of a shop is convinced that the apparently Latin locksmith repairing his back door (Michael Pena) is a black man who will rob him later; he buys a gun from a racist store owner who derisively calls him Osama. There's much more, and no one but the locksmith is exempt from a racist act; in fact a scene between the locksmith and his daughter gives us the one moment of true love and compassion in the film. And ultimately the film comes back to the moment when Cheadle's car is rear-ended.

Haggis as director shows great visual skill and a secure command of his scenes; he has found a way to persuade us of the power inside each vignette without hammering his point home. And the actors are excellent (though Fraser seems too youthful for his role). Dillon, Ludacris and Cheadle particularly all compel our attention when they're on screen. But whenever the film comes close to greatness - whenever, that is, we in the audience have lost ourselves in the power of the moment as we watch - the contrivance of the story pulls us back; it's just a movie after all. No matter how believable Haggis and his cowriter Bobby Moresco make the scenes as they are acted out, the film lacks the resonance of great art. Oh, we say; what's coming up next? And something always does. "Crash" plays like an exercise in screenwriting rather than a lesson for our lives, which is the mark of great art.