The usual limitation of director Costa-Gavras is that he makes well-crafted liberal thrillers that preach to the converted, but this 1988 movie, scripted by Joe Eszterhas, does something rather different. Debra Winger plays a federal agent who infiltrates an underground white supremacist group in the rural midwest. She becomes involved with one of the leaders (Tom Berenger) and ultimately wants out, but she’s forced by her Chicago-based operative (John Heard) to hang on for dear life. Rather than give us stock racist villains, the film offers a relatively three-dimensional view of their life, their community, and their all-American eccentricities. (Berenger’s character, for example, hunts down blacks and teaches anti-Semitism to his cute little girl, but he won’t shake the hand of an American Nazi.) The result is a far from simple look at a subject that most American movies haven’t the guts to go near, with a number of fine performances; Betsy Blair, John Mahoney, and Ted Levine are among the costars. 127 min. (JR)