Byron De La Beckwith, the white racist who killed Mississippi civil rights activist Medgar Evers in 1963 but who evaded punishment until 1994, gets what's coming to him while we get beaten over the head with righteous indignation from filmmaker Rob Reiner. To watch Reiner tell it in this relentlessly pious, self-congratulatory history lesson, Evers was some good black guy who did something or other important for the NAACP and who was shot in the back as he was coming home one night, leaving behind his dignified widow, Myrlie (Whoopi Goldberg) and three children. (His character is on screen for all of two minutes.) The real hero at least according to this morality tale is impassioned white Assistant DA Bobby DeLaughter (Alec Baldwin), who dedicated himself to reopening and winning a case two previous juries could not resolve. Ghosts of Mississippi sets its hectoring tone with an opening montage of images from African-American history, from slave-ship miseries to life in the tinderbox South of the 1960s. Yet, all too soon, the white folks take over, intoning lines (by Unlawful Entry screenwriter Lewis Colick) no living person would ever deliver lines like ''What's America got to do with anything? This is Mississippi!'' Baldwin hammers his way to justice, with exertions notably similar to those of Matthew McConaughey in A Time to Kill. As Beckwith, James Woods (his head larded in latex most of the time as an old man) teeters between portraying evil and its caricature. Goldberg, meanwhile, turns in such a Very Serious Performance you'd think Myrlie Evers (now chairman of the NAACP) is a biblical matriarch, and Goldberg is Vanessa Redgrave. This is movie-as-atonement or maybe as Sunday school lesson.