There's an operatic element to most of Martin Scorsese's recent films that's almost Verdian in its passions and sweep. They've also begun to assume the length of grand opera, which worked well enough for his monumental Gangs of New York, but becomes a stretch with a good cop/bad cop saga such as The Departed.

That's not to say there aren't some substantial themes to be found in his latest film. No one is better than Scorsese at delving into the damaged psyches of violent men who all seem to be searching for a strong father figure — someone to correct their childishly brutal behavior. The Departed also raises interesting questions about loyalty, both to one's tribe and to oneself, and refreshingly refuses to provide answers. The film documents the collisions of men on both sides of the law, and, as the line separating the two worlds is often fluid, the story is necessarily ambiguous. Yet, it feels like a page-3 news item of epic proportions.

The older Colin (Matt Damon) continually rises in the ranks of the cops, quickly becoming a top detective. Another cop hopeful, Billy Costigan (Leonardo DiCaprio), who came from a troubled and confused background, doesn't get much respect from his superiors, who decide the best thing he can do to prove himself would be to infiltrate Costello's gang disguised as a young gangster.

In short, the good cop, Billy, has to become bad, while the bad cop, Colin, continually masks himself as good. Though the two men have a very brief glimpse of each other at the beginning of the film, they will be moving, inexorably, toward a final deadly encounter. The problem is that it takes two hours and 35 minutes to get to it, something that its inspiration, the Hong Kong action drama Infernal Affairs, managed to effect more succinctly.

The story is also hampered by a contrived love triangle involving Colin and Billy (who will never learn of this connection) and a legal aide psychologist, Madolyn (Vera Famiga). But there's an intriguing Cain and Abel aspect of the story, down to casting two leading men, Damon and DiCaprio, who share many physical traits.

DiCaprio has become a remarkable actor, and The Departed really becomes his film. Damon is fine, though we've seen him play off his frat-boy-next-door personality in the role of a villain before. Nicholson is given the film's arias, which he broadly plays as a combination of One Flew Over the Cuckoo's Nest's McMurphy and The Shining's Jack Torrance. Nicholson long ago settled for self-parody over acting, so enjoy the old song.

There's an excellent supporting cast, especially Martin Sheen as Billy's superior Queenan (the good dad versus Nicholson's evil pop), and Mark Wahlberg as Queenan's second-in-command, Dignam.

Surprisingly, given the length of The Departed and the care with which Scorsese creates every scene, the end of the film becomes a confusing jumble. To list the questions that arise would be to spoil the plot, but there are a number of incidents that simply make no sense. It must also be said that the director's final image is the type of bargain symbolism one would expect from a first-time director rather than a master of the craft.