*For a Hollywood legal thriller, “Michael Clayton” strays pretty far from the standard tendencies of many of its predecessors.The title character, played by a worn-down George Clooney, is not a young prosecutor bucking the system, but rather a big-time lawyer at a slimy firm for rich clients. The case does revolve around an evil corporation that knowingly poisoned innocent people, but this is presented without any weepy victims’ stories or any crusading on the part of the main character. And last but not least, there’s no case-breaking discovery during interrogation or grandstanding speech in the courtroom to close the picture.Instead there is a kind of quiet destruction by film’s end, and it is all the more effective.Michael is a fixer, a shadowy figure who cleans up clients’ messes quickly and silently. When his old friend Arthur (Tom Wilkinson) splits with reality (and his clothes) during a deposition for their biggest client, Michael is sent in to smooth everything out. When he, like Arthur, finds out the truth about a carcinogenic weed-killer that the corporation knowingly distributed, he must navigate dangerous waters to save Arthur from himself.Wilkinson is all manic fervor in the showiest role, and will most assuredly be remembered come Oscar time. “Michael Clayton” is also full of excellent low-key performances from Clooney, a coolly manipulative Sydney Pollack (who plays a powerful firm partner), and the conglomerate’s nervous new counsel, played by Tilda Swinton.Screenwriter Tony Gilroy (who penned the “Bourne” movies) steps behind the camera for the first time, and proves to be a talented director of actors. He doesn’t need to make Swinton some menacing corporate monster. She is just a woman who is desperate to impress her boss, and she rehearses her delivery in the mirror, hoping to appear more confident. Her outward behavior is sympathetic, but she becomes a monster in her choices. Her scenes are a big leap away from the familiar structure of legal dramas, and give the film more resonance.Gilroy’s script is not concerned with the intricacies of the case. “Michael Clayton” is about corrupting power and moral choices. There is some complicated legal-speak, but it is used mostly to lend an air of authenticity. The informed, intelligent dialogue and an initially off-putting flashback structure keep the audience on our toes. This is balanced by the simplest screenwriting device of all, though-the “macguffin.” The item that everyone wants and some would kill for is an incriminating document that shows the company’s culpability.Clooney is terrific in a role that asks him to disguise much of the charm and confidence that make him a reliable leading man. What Michael does for a living is not pretty, but Clooney makes him a sympathetic and clearly damaged character. He’s a divorcee paying off gambling debts and a significant loss on a restaurant venture. Reduced to a backroom role in the firm while his peers are all made partners, he refers to his job as “janitor.”A good clean-up man will size up the options and take a clear-headed approach to the problem. Michael has trouble when friendship and ethics blur the lines. The law firm is the only way to bail him out of his financial crisis, but it also has a stranglehold on his life. Knowing Arthur has gone off the deep end, he sees how freeing it is for him. At the same time, his deranged friend has never had a clearer focus.Proving to be quite effective as a visual director, Gilroy stages one terrifyingly efficient point-of-view murder sequence that left me breathless. He also frames his actors in close-up and allows us time to read their faces, like the memorable last shot that lingers long after the credits start to roll, giving you time to measure the effect of the entire film on one actor’s face.Gilroy has crafted a smart thriller that revolves around a corporate cover-up but doesn’t burrow into hair-splitting details and stays away from cliche. A lawyer who develops a conscience is nothing new, but “Michael Clayton” is a rich experience with well-drawn characters that avoids the trappings of its genre.