Lakeview Terrace (15)

Here's some early rain on the parade of America's bright new dawn.

Just as we're getting all excited about Obama and the possibility of change, Neil LaBute's Lakeview Terrace warns us to hang on a minute: those deep-lying social fissures aren't just going to disappear. LaBute didn't write the screenplay – it's by David Loughery and Howard Korder – but the way this film probes and goads is characteristic, and while his near-the-knuckle provocations have usually centred on the sexes (In the Company of Men, Your Friends & Neighbors), this latest pokes around the riskier taboos of race.

Samuel L Jackson plays Abel Turner, a Los Angeles cop and widower who's strict with his teenage son and daughter – he can alienate both of them before breakfast's over – and has a worryingly short fuse at work. A self-appointed security man in his upscale suburban cul-de-sac, he watches the arrival of new neighbours Chris (Patrick Wilson) and Lisa (Kerry Washington) and doesn't like what he sees. Why? He's white and she's black, for a start, but there's also some buried class resentment there, too: these people know nothing of his South Central beat, nor of the threat from the Arroyo Seco stream lying beyond their back fences.

The film is playing a variation on Ray Liotta's maniac cop in Unlawful Entry and also on Jackson's vicious duelling with Ben Affleck in Changing Lanes, stories in which unsuspecting yuppies – remember them? – find their home and hearth under attack. Neither of them, though, has a scene as mesmerisingly tense as the housewarming party in this one. Abel, who has already needled Chris with "white" jibes, arrives amid mellow social small-talk and instantly snitches on Chris for smoking behind his wife's back; by the time he leaves, the guests look stunned by the way he's poisoned the atmosphere.

Jackson plays this simmering control freak with a disconcerting edge – he uses his bulk menacingly, and he tends to smile as he sticks the knife in. "Can't we just all get along?" Chris asks him, innocently echoing Rodney King, but one look at Abel's dark-browed gaze tells us, ominously, no.

The unease of a mixed-race couple, even a securely middle-class one like this, is given a further twist by Chris's awkward relationship with his father-in-law, a patrician fellow who will only look at his daughter when he's talking to them both. The script keeps foregrounding this tension in a way that very few American mainstream movies do. Crash gave Matt Dillon's racist cop some great scenes, but then bottled it with a we-are-the-world denouement. Lakeside Terrace allows the antagonism to simmer just so, and then, regrettably, lets it boil over in a climax of gunplay and a swathe of Californian brush fires, perhaps the most crashingly symbolic conflagration since Apocalypse Now. The odd thing is that the early scenes in which Abel coolly sizes up his neighbours are much more effective than the later stages when he's a loony with a badge.