Martin Scorsese's obsession with pain and suffering--and, more to the point, martyrdom--dates back to his breakthrough 1973 film Mean Streets, whose main character repeatedly puts his hand into a burning church candle to see what the flames of damnation will feel like. This fascination with violence continued in Taxi Driver ("Someday a real rain will come and wash the scum off the street"), Raging Bull, The Last Temptation of Christ, Goodfellas, Casino and Bringing Out the Dead. In all these films, Scorsese has emphasized that for a man on a mission, especially a holy mission, the cheek-turning teachings of the church don't matter. Actions speak louder than words, and bloody action speaks loudest of all. He doesn't condone the violence, or even attempt to explain it. It's just there.

Gangs of New York has been over 20 years in the making. Based loosely on the quasi-historical 1928 novel by Herbert Asbury, it's about the conflicts between Manhattan's Irish immigrants and the locals. The tale begins in 1846, with a bloody street battle between the Nativists, commanded by Bill "the Butcher" McCutty (Daniel Day-Lewis), and the Irish, led by a rough-and-tumble priest (Liam Neeson) who has no qualms about living or dying by the sword. The priest perishes at the hand of the Butcher, an act of brutality that is witnessed by the priest's young son.

At this point in the film, it looks as if Scorsese and his three credited screenwriters are going to follow a traditional story of revenge. The boy grows into a man by the name of Am­sterdam Vallon (Leonardo DiCaprio), who returns to the city 16 years later to kill the man who killed his father. But Amsterdam is more Hamlet than Charles Bronson (who faced a similar dilemma in Sergio Leone's magnificent Once Upon a Time in the West, a film that has clearly influenced Gangs of New York). Amsterdam's hesitation leads to the many complications of the film's second act in which Amsterdam, while assuming the role of the Butcher's protégé, falls in love with a beautiful pickpocket (Cameron Diaz).