Someone once said that the only difference between cops and robbers is the badge.

Rating: 9/10 (13 October 2006)

Well, in this movie, both the Good Guy and the Bad Guy have badges. Ben Affleck is the crooked cop, Colin Sullivan. He works for Frank Costello (Jack Nicholson), an Irish-American gangster whom Sullivan has both feared and idolized since childhood. And, he apparently measures success by how close he can live to the ritzy neighborhood where the Old Boston Statehouse is located.
Leo DiCaprio , on the other hand, plays Billy Costigan. An honest cop whose late father was apparently a nouveau riche gangster who married a Boston Brahmin debutant. And, so, he has spent most of his young life feeling like an outcast in both the blue-collar and green-collar parts of Beantown.
Costigan is recruited to spy on Costello's mob, so that Capt. Queenan (Martin Sheen) can finally send his old rival to prison. While Sullivan, of course, is paid to keep that from happening! In a way, then, these two young men are just pawns in a real-life game of chess, where Queenan and Costello are the players.
But, in a major piece of irony, the pawns _become_ the players after the deaths of both Queenan and Costello! And, caught between them is Madolyn, the psycho-analyst they both fall in love with.
Just like in "Taxi Driver," Martin Scorsese proves that morality is not so much black-and-white as various shades of gray. And, it's very hard to tell the darker shades from the lighter ones. The only reason I don't give this a perfect ten? The violence and swearing get a little excessive. Even for an R-rated movie!
But, I still recommend, most heartily, that you go see it.