Based on Herbert Asbury's history of criminal New York in the mid-19th century, this is nothing less than Scorsese's Birth of a Nation. Irish immigrants are flooding the city, while the poor club together in rival ethnic gangs. You can sense the director's excitement at this virgin cinematic territory: Gangs of New York won't establish a new genre, but it does suggest the missing link between the frontier Western and the gangster movie. Cinephiles will find echoes of The Wild Bunch, Heaven's Gate, Leone and Visconti in the mix, yet the director has modulated the nervy syntax to fashion what is meant to be his most accessible movie - the percussive rock score and wan romantic clinches between DiCaprio and Diaz are firmly in the blockbuster idiom. Predictably, her role as a pinchpurse by the name of Jenny remains undeveloped. And because she's the lynchpin in the surrogate Oedipal revenge drama between DiCaprio's angry Amsterdam Vallon and Day-Lewis's ferocious crime lord Bill the Butcher, that's a real drawback. Despite the long running time, the film's relationships all feel malnourished, with things getting especially sketchy around the two-thirds mark. Even so, it's never less than compelling, driven by an overwhelming, larger than life performance from Day-Lewis and by Scorsese's grandiose historical imagination.