The main idea of 25th Hour is so strong, I almost wish it had been protected from Spike Lee’s mind. But if it’s to Lee that this film owes its crudeness, unevenness, and stridency, it’s also to him that it owes much of its emotional force.

The story unfolds on the last day before Monty (Edward Norton), a successful drug dealer who’s been caught by the DEA, must report to prison to serve a seven-year sentence. Because Lee and screenwriter David Benioff (who adapted his own novel) take their time about making Monty’s predicament explicit, the tension and sadness get a chance to exist on their own. At its best, 25th Hour is a film of moods, where what’s not expressed is more important than what is. Much of the dialogue consists of avoidance maneuvers by which Monty and those close to him — his girlfriend (Rosario Dawson), his father (Brian Cox), and his two best friends, Frank (Barry Pepper) and Jake (Philip Seymour Hoffman) — circle around the hopeless reality.

The film is immersed in New Yorkishness. The main titles appear over a romanticized nocturnal Manhattan skyline. Lee takes us on a tour of Manhattan: an esplanade along the East River, the trading floor of an investment bank. The narrative is filled with the kind of chance encounters whose possibility is so important to city life: Monty picking up a wounded dog, a prep-school teacher and his student running into each other outside a club. And New York multiculturalism is a big part of the movie too: Monty visits his dad’s "Irish" bar, mixes with Russian and Ukrainian gangsters, and has a Puerto Rican girlfriend.

It’s in trying to make New York an explicit theme rather than a pervasive presence that 25th Hour goes wrong — disastrously. The sight of the words "Fuck you!" scrawled in the corner of a bathroom mirror in a bar touches off a long rant in which Monty says "Fuck you" to everything that bothers him about New York: Pakistani cab drivers, Korean grocers, gay men, and so on, each target appearing on cue in a montage of snapshots of stereotypes. No doubt Lee wants to shock us viewers out from behind our PC cover and get us to admit that we all view people as stereotypes. But he makes it too easy for us to reject Monty: the stereotypes are all images that would flash inside the skull of a rich white heterosexual male New Yorker with no political awareness. By the time Monty reaches "Fuck Osama bin Laden," Lee’s presumption of a visceral response from the audience is as unpleasantly clear as the irrelevance of the scene (or the response) is to the main concerns of the movie.

The next low point comes in a scene in Frank’s high-rise apartment. The camera creeps up to Frank and Jake and tilts down, revealing a perfect view of Ground Zero through the window. (Juxtaposed with this image, the Middle Eastern vocal in Terence Blanchard’s terrible score can only be heard as a reference to al-Qaeda.) The use of Ground Zero as a backdrop for the friends’ bad faux improvised dialogue is insulting. It’s irrelevant to the scene, which is itself gratuitous (reviewing Monty’s situation, the two men merely state things the audience already knows or can figure out). I suppose both this scene and the bathroom-mirror one can be defended as "essayistic" and "Godardian" — as if Lee were making a movie about whatever’s on his mind. But no essay should be as exploitative and pretentious as this one, or, for that matter, as the unctuous, overwritten encomium on rural America, recited by Brian Cox as if he were narrating a Chrysler industrial, that mars the film’s striking conclusion.

If in spite of everything 25th Hour is affecting, that’s partly because there are some fine performances, especially Norton’s, and because the terrible energy of the theme of Monty’s last night of freedom charges the atmosphere of the film’s best section — a long sequence in a nightclub. The narrative flow is casual and evocative, and Lee’s pace is relaxed enough to let him revel in an extended-time shot of Anna Paquin’s high-school student, moisture glistening on her Ecstasy-sensitized skin, moving across the room as if she were picking her way over the bodies at an orgy. The sequence, combining a sense of pleasure in spending time with the haunting awareness that time is being wasted, is the heart of the film, and by itself it justifies 25th Hour.