Lately addiction seems a frighteningly apt social metaphor. America’s oil jones has been publicly acknowledged by our president, himself an untreated alcoholic, but there’s so much more: we’re also addicted to compulsive shopping and corn syrup, to drugs from amphetamines to Zoloft, to cathartic violence. It’s a pattern that keeps repeating itself: the initial world-beating high (“Mission Accomplished!”), the long slide into more and more overt dysfunction, the isolation from those who once cared for us, the hysterical denial of increasingly ugly, increasingly undeniable facts, the crashâ?¦and then, too often, the same all over again.

These ruminations are provoked by Half Nelson, a beautifully made film that explores the conjunction of the personal and political with unusual intelligence and compassion. Although this indie effort by first-time filmmakers Ryan Fleck and Anna Boden (they wrote, he directed, she produced) is unabashedly left-leaning, it’s art, not a tract. Which is to say that Half Nelson presents a world so rich in feeling and insight that the merely political is overwhelmed by the tragic, whether Fleck and Boden intended it or not.

This teacher’s pet is the monkey on his back. © 2006 Think Film Company, Inc.

Ryan Gosling plays Dan Dunne, one of those young middle-class idealists trying to make a difference by working at a junior high in a poor section of Brooklyn. He’s teaching history to a roomful of black and brown 13-year-olds and coaching the girls basketball team, and we can see his passionate belief in these kids and his anger at the lousy hand society deals them. But behind his talk of dialectics and social change we also sense a dangerous vulnerability.

Soon it emerges that Dan’s recreational use of cocaine is sliding into a full-blown crack addiction, apparently not for the first time. “I cleaned up for the most part,” he insists to a woman he’s picked up in a bar as he snorts a line. “I do it now to get by.” Even as he attempts to give his students an alternative to poisonous despair, he is succumbing to it himself.

When one of his pupils, Drey (Shareeka Epps), finds him collapsed in the locker room after a game, the glass pipe still in his hand, she knows what’s going on. Her brother is in prison for dealing drugs and now his smooth-talking dealer boss (Anthony Mackie) is pursuing Drey with offers of cash and friendship. Dan seems almost relieved that someone from the daylight side of his life finally knows the truth about what’s happening to him, and he pulls himself together to give a ride home to the stolid little girl, whose father has once again failed to show. Gradually a wary, codependent friendship develops between student and teacher, each frightened by what they foresee in the other’s future.

Several things make this story not only satisfying but revelatory. Most striking is the acting, which is breathtakingly good. Gosling is riveting in every moment of every scene, capturing perfectly the heartbreaking charm of the addict and the self-loathing lying behind it. Wrung out and strung out, the actor so completely inhabits his character that it’s hard to believe he isn’t rehab-bound in real life.

Epps, discovered by the filmmakers in a Brooklyn school, is an amazing presence, able to convey an array of conflicting emotions in a glance. She portrays innocence and its loss without a flicker of falseness. As the dealer, Mackie is a charismatic combination of velvet and steel serenely unaware of his own corruption. In a brief but heartbreaking scene, Deborah Rush and Jay O. Sanders, as Dan’s parents, suggest decades of dashed hopes and self-protective denial.

The script is full of telling moments. Without spelling anything out, Fleck and Boden know how to reveal whole lives through offhand remarks and small gestures. Thus we recognize how lonely Drey is when we see her come home to an empty apartment—her hard-working mother, a paramedic, is being forced to do another double shift—and switch on the blaring TV. We see the self-image Dan is clinging to, and its disintegration, when he declaims to another bar-room acquaintance, “If you can teach just one kid”—only to have her boozily interrupt with “you can teach them all.”

Although this isn’t a downbeat film—indeed, it’s often quite funny—it seems drenched with sorrow, the sorrow of knowing that living in an unjust world is often more than people can bear. This is a sentiment that seems to be all around us lately, including in some of the best movies of the moment. Heading South deftly, devastatingly shows the middle-aged American women seeking pleasure on the beaches of Haiti as anguished imperialists who can’t help destroying what they love. The hapless family in the hilarious, bittersweet Little Miss Sunshine, desperate to be winners, suffer one loss after another. Perhaps the times are so out of joint right now that only sadness feels true.

One vector for Half Nelson’s sadness and its truth is its visual loveliness. Shot in some of the poorer sections of Brooklyn, its bleak setting of abandoned lots and rundown rooms is hardly the stuff of coffee-table books. But the filmmakers aren’t afraid of artiness, and the flow of images (the clear light in Dan’s classroom, the vistas of sky and water amid Gowanus’s industrial grunge, the jumpy wooziness of the nighttime streets) adds an element of visual poetry. The soundtrack, by the Canadian collective Broken Social Scene, is wonderful, too.

Half Nelson rigorously avoids the clichés of redemption but maintains a mood of cautious hopefulness. Dan teaches his class that the dialectical clash of opposites is the engine of change, and perhaps the unlikely alliance of a disillusioned white teacher and a young black girl is meant to signal a turning point for them both.

But the hope that wafts through Half Nelson may partly be due to the way the story evokes one of our most beloved cinematic fantasies: the moral salvation of a struggling Caucasian by the friendship of an African-American. This is probably not intentional; certainly Drey never stoops to anything like Halle Berry’s cringe-making assurance to wizened Warren Beatty in Bulworth, “You my nigga.” But even though the movie doesn’t crudely play the race card, our collective reflex is to infer that the white man’s better self is going to prevail just because a black girl is willing to stand by him.

Of course, reverse the races and the film would probably fall apart. If this were the story of a sweet little white girl befriending an increasingly out-of-control crack-smoking black man, we might find it a lot more difficult to believe that the teacher won’t sooner or later violate the student’s trust, perhaps catastrophically. That’s not just knee-jerk racism but recognition of the realities of addiction: junkies of any color are not the most trustworthy friends for impressionable youngsters.

After all, if caring about children like Drey were enough to save Dan, he wouldn’t have gone off the rails in the first place. As he comes undone, his classroom lectures about opposing the machine and fighting for change begin to sound like the impotent spleen of, well, a crackhead. His anguish is not just a cause of his downward spiral; it’s also an excuse for falling still lower.

What provokes people to save themselves is mysterious and unpredictable, but Half Nelson’s portrait of a man being destroyed by his demons is so real that an easy way out for Dan seems about as plausible as a simple solution to America’s sociopolitical quandaries. Maybe Dan and the rest of us won’t get the monkey off our backs until we hit a much harder, much more cataclysmic bottom.