By Sean Burns

Are we at last prepared to admit that Woody Harrelson has grown into one of the greatest actors of his generation?

It may sound like balderdash to fans of his friendly barkeep on Cheers, but there’s a slippery sociopathy hiding just beneath his drawl, which director Oliver Stone seemed to pull out of nowhere for Natural Born Killers.

Harrelson has always been a brilliant comedian, but something more sinister is lurking behind his eyes.

He hasn’t made it easy to be a fan. Harrelson tends to disappear for years, often more concerned with his weed-friendly dietary regimens than his movie career. Any other actor would’ve tried to capitalize on his brilliant performance in The People vs. Larry Flynt, but Harrelson just noodled around on Broadway and all but vanished for a decade or so.

He’s back with a vengeance in director Oren Moverman’s Rampart. It’s a terrible movie that only works on the rare occasions when Harrelson’s searing performance is allowed to shine.

Harrelson and Moverman previously worked together in The Messenger, an Iraq war drama with Harrelson’s slow-burn rendition only occasionally upstaged by gratuitous long-takes and I-went-to-film-school camera shots. That well-written, well-acted movie suffered from an acute case of “Look, Ma, I’m Directing!” syndrome.

At times, Rampart is almost unwatchable, as Moverman gimmicks up every interaction with art school flourishes. Entire dialogue sequences are conducted with our only vantage point locked behind the back of a character’s head, and crucial moments are so over-conceptualized that the camera often glides upwards, mid-sentence, into a distracting, unnatural angle for reasons that don’t make much psychological sense.

It’s a shame, because Harrelson is magnificent. The actor stars as Dave “Date Rape” Brown, a bullheaded, racist cop caught in the late 1990s Rampart division scandal that rocked L.A. Starved down to sinew and raw attitude, Dave seems to subsist on cigarettes, martinis and xenophobic bluster. The running joke in the movie is that he doesn’t even eat.

But Dave’s days of busting heads and torturing suspects are quickly coming to a close. Too bad he’s the last one to notice. Positioned as a fall guy for the department after a Rodney King–style beating, he’s suddenly up to his ears in inquiries from Sigourney Weaver. Then Steve Buscemi makes a cameo as the camera drifts away on some sort of lazy-Susan apparatus.

Dave lives in a modest suburban sprawl with his daughters and two ex-wives—who happen to be sisters. At night, he drinks his way through dinner until he’s finally boozed up enough to choose a companion. (Whichever casting director picked Anne Heche and Cynthia Nixon to costar as siblings deserves some sort of special award.) Other nights he finds himself shacked up with Robin Wright’s no-nonsense defense attorney, a terrible idea made all the more attractive because of how wrong it is.

Scripted by Moverman with novelist James Ellroy, Rampart will feel familiar to fans of the great writer’s work. Ellroy has already made a career out of chronicling bad cops on the mean streets of L.A. If Harrelson’s character rings a bell, it’s because Kurt Russell already played him to perfection in the Ellroy-penned Dark Blue, and then Keanu Reeves tried his best, with less success, in 2008’s Street Kings.

The difference between Rampart and those earlier Ellroy projects is that Moverman never aims for a view of the larger world. From start to finish we remain locked in the first-person worldview of Dave “Date Rape” Brown, and as his bullying way of life finally collapses around him, there’s no sense of escape or relief. Moverman’s annoying camera placements keep us firmly locked into the antihero’s perspective, no matter how much the audience may need to take a break from him.

It’s a daring gambit that ultimately proves suffocating. Harrelson is just too good at being a sociopath, and the film gets bogged down with a sorry subplot involving a dirty ex-cop played by Ned Beatty. Rampart is so narrowly focused, you’ll wish just one character would provide some form of comfort.

Yet the performance still haunts. Lean, insinuating and spouting some of Ellroy’s most colorful invective, Harrelson leers and slurs his way through the movie. Always teetering on the edge of violence, he’s odious and magnetic.

Rampart

Starring Woody Harrelson, Robin Wright, Cynthia Nixon, Anne Heche, Sigourney Weaver, Ben Foster, Ned Beatty and Ice Cube. Written by James Ellroy and Oren Moverman. Directed by Oren Moverman. At Boston Common.