The film is not in chronologically told film but we see early scenes before Derek is turned either way. He firsts listens to some extreme remarks by his father, and then we later see him in his grief after the killing of his father. Norton is decent enough in portraying the natural reactions of Derek in both circumstances but these scenes are too simplistic for him to really give a us a pinpoint on the cause of Derek's path to being a Neo-Nazi.
Derek instantly becomes an integral member of a local groups of Neo-Nazi white supremacists. Norton terrific in a very chilling way in these scenes. He is oddly charismatic while he makes his racist remarks. Norton shows the right oddly misplaced passion in these scenes, that makes these scenes especially disconcerting. Norton shows that Derek is not a dumb guy really, and that even a smart person can simply be lead this way. Norton makes Derek's hatred very realistic and that is pivotal for the film. He never seems to be acting the racism but rather that it is simply part of Derek's world view.
Two scenes in particular are especially made very effective due to Norton. The first when he gets in to an argument with his family over his views, and fights with everyone. The strongest moment though is when he shows some regret to his mother and sister of the violent way he reacted. Norton correctly shows here that although Derek is a racist, he still yet is a human. The other scene though is his scene where he kill two black men who break into his car. Norton is chilling here showing Derek's hate in its purest form. His smile at the very end of the scene is especially effective. Norton portrays the true viciousness of Derek in this state and the real nature of his hatred in this moment.
Derek is sent to prison after his murders, and meets up with other supremacists inside the prison. Norton performance here is essential to the film, and an extreme challenge. He at first still acts like he has before, but becomes disillusioned with his cohorts due to their lack of beliefs. He is then beaten and raped by them for leaving their group, and for befriending a black inmate. Norton transformation is effective as he acts his cocky self at the beginning of his prison, but starts to see his hate as pointless as incorrect. A lesser part of his performance is in his friendship with a black inmate which is probably a bit too simplistic in terms of its writing. Norton can't quite sell this aspect of it, the abuse of the others turning him is more believable, as this side shows Derek basically losing his hatred due to finding the other inmate being funny. He's never bad, but he can't fully overcome the materials limits.
After getting out prison Derek has become just about completely reformed, now wishing to help his struggling family and set straight his Neo Nazi younger brother (Edward Furlong). Derek is now a man who regrets his actions, and tries his best to rectify them. His portrait of Derek is honest and absolutely convincing as he confronts his brother and his former friends over their racism. He handles all of these scenes with the the right poignancy. It is fascinating how Norton can make the transition from a chilling hate filled character to a honest good man. Norton also is quite heartbreaking at the tragic ending of thee film. Although moments of the transition are weakened by the writing involved with the film the two sides of the performance Norton does pull of incredibly well.