This oft-overlooked James Woods vehicle is a challenging but memorable thriller. Cop has two very strong things going for it. The first is that the film convincingly captures the seedy side of Los Angeles, making the atmosphere of failed dreams gone sour palpable without ever overplaying its hand. The other is an amazing, totally committed performance by James Woods, who effortlessly convinces the audience of his character's all-consuming need to punish evil, no matter the cost to him or those in his way. That said, Cop is so focused on its hero and his dark obsessions that it might alienate a good portion of its potential viewers. The film makes no attempts to disguise the fact that Lloyd Hopkins' obsessions have made him cross the line into amorality, and most of the other characters are portrayed as either contemptible (Charles Haid's corrupt cop) or pitiful (Lesley Ann Warren's emotionally damaged poet). That said, the supporting performances are good across the board: Haid and Warren make the most of their limited roles and Charles Durning is convincing and likeable as Woods' seen-it-all mentor. Also, the film's refusal to back off from its twisted vision inspires a certain respect in anyone who can appreciate cultish, left-of-center fare. Ultimately, Cop might be a bit too nihilistic for those used to more conventional cop drama fare but it's well worth the time for those thick-skinned viewers who can stick with its tough agenda.