CHRISTY LEMIRE — "Michael Clayton" might have been a standard thriller -- one that's as generic and forgettable as the title itself -- were it not for some sharp writing from Tony Gilroy and an intelligent, subtly powerful performance from George Clooney.

As a "fixer" at a prestigious New York law firm, Clooney gets to show all the charisma of the dazzling Danny Ocean as well as the vulnerability of his Oscar-winning role in "Syriana." He just keeps getting better with age, and it's breathtaking to watch this former People magazine "sexiest man alive" show absolutely zero vanity as he expands his range.

Gilroy, directing for the first time after writing or co-writing all three "Bourne" movies, gives Clooney a meaty part to work with, even though it's one that's rarely flashy. His Michael Clayton is stuck handling the dirty work for lawyers with more clout than him at Kenner, Bach & Ledeen, stuff like hit-and-runs and volatile mistresses and wealthy kids in trouble. After 15 years, he still hasn't made partner and some bad business decisions have left him nearly broke. Divorced but still trying to be a factor in his young son's life, he carries the cumulative weight of a lifetime of disappointments in his eyes, his voice, the way his shoulders hunch.

And yet, Michael still responds proficiently and professionally to whatever challenge is thrust upon him. He gets one of his tougher assignments when the firm's top litigator, Arthur Edens (a raving, raging Tom Wilkinson), goes off his meds and has a meltdown in the middle of defending an agrochemical company against a $3 billion class-action lawsuit. Seems Arthur discovered a missing document that spells out the company's culpability, which makes him doubt everything he's built a career on -- which, in turn, prompts Michael to do the same.

Gilroy skips around over the course of four days and lets us put the pieces together, beginning with Arthur's darkly funny rant over the opening titles (don't show up late or you'll miss it) and a stunner of a warning that Michael might be messing with the wrong people. Along the way, he clashes with the chemical company's chief counsel (Tilda Swinton, jittery beneath the bravado), whose career also would be destroyed by these damning revelations; some quasi-bad guys Michael and his brother owe money to for a failed restaurant outing; as well as his own boss at the firm (Sydney Pollack), who urges him to stay the course, no matter what.

It seems totally appropriate that Pollack is here -- almost like an homage -- since "Michael Clayton" feels a lot like the kind of smart, cynical thriller he would have directed 30 years ago. Gilroy wisely refrains from melodrama, and the stark cinematography from Robert Elswit (who also shot Clooney's "Good Night, and Good Luck" in gorgeous black-and-white) adds to the steadily tense mood.

Yet there are some plot points that may not bother you while you're watching them unfold because you're too engrossed, but they'll nag at you afterward. Certain characters' decisions don't always ring with complete plausibility; people who were meticulously careful in one instance get sloppy in the next. And Gilroy probably should have expanded on the interaction between Michael and his son or left it out entirely. As is, it feels a bit wedged in, though their relationship does result in one unexpectedly touching bit of fatherly advice.

Gilroy also has come up with a genius way to get his audience to stay through the closing credits. It's so simple and effective, it's amazing no one directing Clooney thought of it before.

Running time: 118 minutes.

Three stars out of four.