How can you run for office and have anything left?

"The Ides of March" tells me something I already knew: that the experience of running an American political campaign is crushing for body and soul. By the time a winning candidate survives more than a year of primaries and the general election, it is a wonder he has the strength remaining to govern. The film also raises the question of whether it is possible for any candidate to win and yet remain true to his original values.

Although the movie stars George Clooney, well-known as a Democrat, it doesn't target or even really consider Republicans. It takes place entirely within a Democratic primary campaign, and although our feelings about who is good and bad may evolve, they're all Democrats.

The central character is Stephen Meyers (Ryan Gosling), who as a press secretary is required to more or less lie as a living. He works for Pennsylvania Gov. Mike Morris (Clooney), an idealistic liberal. Philip Seymour Hoffman is Paul Zara, his seasoned campaign manager; Michael Mantell is Sen. Pullman, Morris' opponent, and Paul Giamatti is Tom Duffy, Pullman's campaign manager. A strong cast. Perhaps because the screenplay is based on a play ("Farragut North" by Beau Willimon), it contains some front-of-the-stage monologues that Hoffman and Giamatti make plausible under the closer scrutiny of a camera.

All of these men, except young Stephen Meyers, are realists. They're cynical, compromised and sometimes underhanded, but all in the cause of something they believe in. The Gosling character believes mostly in himself. Like many staff members of powerful men, he confuses reflected glory for the thing itself and dreams not so much of Gov. Morris winning as of being able to rise in the staff ranks and take over Zara's job.

This all happens in the pressure-cooker atmosphere of the Ohio primary, where the big picture is painted in tiny vignettes: campaign stops, hand-shaking, speech writing, sleep loss, and bone-deep exhaustion that drives the characters almost to the breaking point. Imprudent sex under these circumstances is explicable, and Stephen puts the moves on a young intern named Molly (Evan Rachel Wood). This allows him to use her naivete to learn information she doesn't realize she should ever, ever share. He also develops a cagey relationship with a journalist (Marisa Tomei), as they work each other for information.

The screenplay, written by Clooney, Grant Heslov and Willimon, is ingenious in the way it meshes personal and political ambitions, especially when Duffy, the manager of the rival campaign, reaches out and tries to recruit Stephen over to his side. His motives are suspicious: Does he really want the guy, or does he know that a job offer is a useful ploy? Certainly Stephen is on the make and looking for openings to his advantage.

Clooney as director seems attracted to stories about smart men under pressure ("Good Night, and Good Luck," "Confessions of a Dangerous Mind"). He draws back from action and plunges into intrigue. Here he conceals certain of Stephen's inner workings (some planned, some improvised) to great effect, as the young man reveals an amorality that surprises even the hardened pros he works under. The last shot of the film, a closeup of Ryan Gosling, held for a long time, is chilling.