FILMGOERS AROUND THE world have had a long-standing romance with the American Mafia. Beginning with Howard Hawks's 1932 classic, Scarface, through the trilogies of Francis Ford Coppola (The Godfather, Parts I-III) and Martin Scorsese (Mean Streets, GoodFellas and Casino), audiences have identified with these stylized, ultra-violent melodramas about honor and betrayal set in colorful, close-knit Italian-American communities. At their best, these sagas have also served as heightened metaphors for the ruthless way power is exercised in this country and the dark side of America dream.

Donnie Brasco was the alias of real-life FBI agent, Joe Pistone, who spent six years undercover with the Mob, beginning in 1976. His masquerade was one of the most successful in American law-enforcement history, resulting in more than 100 organized crime convictions. Pistone/Brasco's achievement depended on his friendship with a low-level Mafia hit man, Lefty Ruggiero, whom he's finally forced to betray.

Brasco (Johnny Depp) has established himself as a small-time jewelry fence in Brooklyn when Ruggiero approaches him with a diamond. The undercover agent correctly appraises it as a fake and goes with the gangster to rough up the bar owner who'd tried to use it as payment for a Mafia debt.

Impressed by the younger man's willingness to use his fists, Ruggiero vouches for Brasco to a local Mob family. The aging enforcer makes it clear he's a dead man if his protégé ever makes a serious mistake or rats to the cops.

On the surface, the story seems familiar enough, resembling other mob movies and TV shows. But British director Mike Newell (Four Weddings and a Funeral) and screenwriter Paul Attanasio (Quiz Show) have thrown out most of the action-set pieces usually associated with the genre and concentrated instead on complex character development. The drama unfolds in a low-key, carefully-observed manner, closer in tone to Arthur Miller's realistic play about friendship and betrayal among Italian Americans, A View From the Bridge, than to the brilliant operatic fantasies of Coppola or Scorsese.

Ruggiero is shown to be well past his prime, and despite repeatedly bragging about his 26 hits, he's afraid of being put out to pasture. Clinging desperately to his lower-middle-class lifestyle, he grouses about how hard he works and how little he has to show for it, complaints typical of any passed-over, middle-aged employee in a large organization.

Ruggiero is divorced, and his son has become a junkie. To fill this emotional void, he takes Brasco under his wing, tutoring him in the ways of the Mob. The younger man learns that “wise guys” never grow mustaches or pay for their drinks, and that they should always sport well-tailored slacks and drive Cadillacs. The veteran hit man also believes in showing genuine respect for the Mafia hierarchy, who often treat him like dirt. “This is your family,” he instructs Brasco and counsels the younger man to follow the Mob's orders without question.

The undercover agent is moved by the over-the-hill gangster's affection, but his success in penetrating the Mafia has created problems in his personal life. His wife (Anne Heche) sees him only a few days a month and is worried that their three daughters are growing up without a father. When Brasco is prevented by his work from attending his eldest's first communion, he's threatened with divorce.

Brasco's Mafia masquerade has also begun to warp his personality. His immersion in the gangster lifestyle has become so complete he can no longer step out of character with his family or his law-enforcement superiors. He continues to talk and strut with mobster bravado, slapping his wife around during an argument and telling off his FBI bosses in a profane, abusive manner. “I'm not becoming like them,” he confides to his spouse. “I am them.”

Brasco's double life begins to unravel when the Bureau forces him into a sting operation in Florida. Another undercover agent has taken over a rundown bar in Miami but can do nothing with it. Against his better judgment, Brasco is ordered to persuade Mob boss Sonny Black (Michael Madsen) to move to Florida and set up a gambling operation in the bar. Everything goes forward as the Bureau intends, but the local cops unwisely bust it on opening night. Ruggiero smells a rat. However, Sonny erroneously concludes that a long-time associate, Nicky (Bruno Kirby), is the culprit.

The whole incident triggers a gang war in which Sonny's faction comes out on top. Brasco has so pleased his Mob bosses that he is to be inducted into the Mafia as a “made guy” as soon as he and Ruggiero execute a rival gangster.

But Ruggiero suspects his protégé, not Nicky, is the informer. Brasco skillfully plays upon their friendship to allay his mentor's fears. Then to assuage his conscience of the approaching betrayal, he offers to give Ruggiero $300,000, illegally held back from the Bureau during the sting, if the older man will quit the Mob life. Ever the loyal soldier, the aging enforcer refuses.

In a surprise move, the FBI arrests everyone while the two are stalking their hit. The filmmakers keep it ambiguous as to whether Brasco would have gone through with the assassination if the Bureau hadn't stepped in. He's then revealed to the Mob as an undercover agent, and his mentor, Ruggiero, is eventually killed.

It's during this part of the action that the movie makes its only misstep. Instead of continuing to concentrate on Brasco's conflicted feelings, the filmmakers fall back on the clichés of the genre and go for the violent set pieces.

This movement away from the char-acter's inner struggle at the moment of truth deprives the movie of its moral center, making it unclear as to whether the filmmakers consider the undercover agent's betrayal right or wrong. Nevertheless, despite this significant lapse, Donnie Brasco stands out from most movies of this genre as an emotionally honest drama and one of the more realistic portraits of Mob life in recent years.

John Prizer is based in Los Angeles.