`THE DEVIL'S ADVOCATE' DELIVERS ONE HELL OF A GOOD TIME.

Byline: Bob Strauss Daily News Film Critic

Some movie concepts are just naturals. Al Pacino running Satan's law firm, for example.

``The Devil's Advocate'' is a delightfully decadent and trashy camp thriller that takes too much time setting up its obvious premise, but knows enough to pay it off with lip-smacking, forked-tongue relish.

The movie doesn't really register on the scare meter, and it's debatable whether anyone involved in the project, other than Pacino, really understood how funny the whole thing was. But as a wacko modern fable about the soul-snatching perils of success, it's more fun than a New York orgy - which it often resembles.

Our compromised hero is drawling charmer Kevin Lomax (Keanu Reeves), a Gainesville, Fla., defense attorney who we meet as he's getting a guilty-as-sin child molester found innocent. Lomax has a few moral qualms about the case, but hey, he's a pro - and he doesn't like losing. Or so he thinks, since he never has lost one, which is why he's summoned to the high-powered Wall Street firm of Milton, Chadwick and Waters.

The head guy, Pacino's John Milton (nudge nudge), is an earthy, ingratiating charmer, even if he does have remarkably yellow teeth, lines like cobwebs around his eyes and a weird fixation on riding the subways. He offers Lomax scads of money and a huge apartment in his very own Upper West Side building, which bears a remarkable resemblance to the nearby Dakota. Lomax's sexy wife, Mary Ann (Charlize Theron), who might just as well call herself Rosemary, initially thinks it a perfect place to raise her long-desired family.

But then things start unraveling. Mary Ann feels uncomfortable at Milton's power parties (his friends include such likely real-life suspects as Don King and Sen. Al D'Amato). Kevin's ever-increasing workload, which includes defending a billionaire developer (Craig T. Nelson) accused of murdering his family, comes between them. Mary Ann starts having visions of the other legal spouses morphing into demons. Kevin hallucinates a sexy co-worker (Connie Nielsen) while making love to his wife.

Mary Ann becomes increasingly delusional and depressed. Milton suggests Kevin drop the case and tend to his wife. Kevin refuses, rationalizing that he doesn't want to resent her for it in the future. Al, who has been uncharacteristically self-controlled up to this point, allows just the slightest perceptible expression of ``Gotcha!'' to cross Milton's face.

``Devil's Advocate's'' droll glory rests in its stubborn reluctance to degenerate into a horror film and remain the looniest of ethical comedies instead. ``Vanity, it's my favorite sin,'' Milton exults during his closing summation - an outlandishly profane rant for which Pacino finally cuts loose like the deviled ham we know he is. Vanity is certainly Lucifer's crowbar throughout this movie. Kevin's ego digs his circle of hell; Milton just hands him the shovel. Yet Kevin is hardly evil or even without compassion, just human like any of us.

Of course, among his legion of names, Milton is particularly pleased to cite the Last Humanist.

Just waiting for Pacino to chomp up production designer Bruno Rubeo's witty, plush-yet-purgatorial scenery is one of the film's many guilty pleasures - we know it's bad when Al goes into ``Scent of a Woman'' overdrive, yet we long for it here like we would a crisp, juicy apple.

Of course, the Master of Deception steals every scene he's in. But Reeves is generally solid until Kevin's moral predicament demands just too much of the actor; similarly, Theron draws sympathy, but grows less convincing as Mary Ann becomes increasingly hysterical.

Director Taylor Hackford and one of the screenwriters, Tony Gilroy, did some very interesting things with Stephen King's potboiler ``Dolores Claiborne'' last time out. They've brought that same unsettling mixture of slick production values and mordant ethical confusion to this adaptation of Andrew Neiderman's novel, where the tone is even more in tune with the original material.

This movie is so tricky that even its cop-out, John Grisham-style happy ending - a creative deal with the devil if there ever was one - ends up fodder for a tricksterish twist.

As I said, a concept like Satan's law firm just can't help but work. This is something everyone in the movie business should know in their bones.

THE FACTS

The film: ``The Devil's Advocate'' (R; nudity, sex, violence, language).

The stars: Keanu Reeves, Al Pacino, Charlize Theron, Jeffrey Jones, Judith Ivey, Connie Nielsen and Craig T. Nelson.

Behind the scenes: Directed by Taylor Hackford. Written by Jonathan Lemkin and Tony Gilroy, based on Andrew Neiderman's novel. Produced by Arnon Milchan, Arnold Kopelson and Anne Kopelson. Released by Warner Bros.

Running time: Two hours, 23 minutes.

Playing: Citywide.

Our rating: Three Stars.

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Photo

Photo: Al Pacino, top, runs Satan's law firm, at which Keanu Reeves is a defense attorney, in ``The Devil's Advocate.''