The film is a concentrated, unrelievedly serious and cerebrally involving entry, exhaustively detailing the true-life saga of a Gotham detective who turned Justice Dept informer to eke out widespread corruption in his special investigating unit during the 1960s.
Treat Williams is outstanding as the young, gung-ho cop who is courted by federal investigators and finds himself on a conscience-wracking approach-avoidance track that finally leads him to accept the informant role.
As Federal pressure for indictments mounts, however, matters quickly careen out of control and Williams is cajoled, manipulated and ultimately blackmailed into spilling everything, while friends spurn him or commit suicide, his protectors are promoted upstairs, Mafiosi attempt buying him off, then try bumping him off, and the Feds barely agree not to prosecute him for his own past sins.
Within a nightmarish, frequently Kafkaesque atmosphere of intense danger and uncontrollable conscience, the film paints a world where law and morality are only relative commodities.
Director Sidney Lumet is in firm control of the sprawling canvas, showing in spades his ability to harness intense energy and almost uniformly top-rate performances from a cannily-cast stable of solid character actors.
1981: Nomination: Best Adapted Screenplay