Written and directed by veteran documentarian Stanley Nelson ("The Black Press: Soldiers Without Swords"), "Freedom Summer" expertly combines archival footage and photos with contemporary interviews to recall the pivotal 10-week period in 1964 when hundreds of activists, black and white, worked together to register African-American voters in violently segregationist Mississippi. Airing on PBS in June to commemorate the 50th anniversary of the events, and certain to become a widely employed educational tool thereafter, Nelson's film is a well-shaped and powerful reminder of a time in recent American history when white supremacy was decisively and courageously undercut.

In its early reels, "Freedom Summer" carefully establishes early '60s-era Mississippi as a racist stronghold, a state in which black people were second-class citizens, expected to bow their heads to whites or step off sidewalks until they passed. Nelson and his interview subjects, including "Freedom Summer" author and historian Bruce Watson, make clear that this monstrous culture was enforced by terrorism in physical, political and economic forms. In a bloodcurdling comment, former White Citizens' Council member William Scarborough says that the Ku Klux Klan wasn't needed in Mississippi because his group's legal efforts were so effective.

At the same time, this council's success unwittingly helped make Mississippi the focus of attention for large numbers of activist organizers and citizens, including more than 700 student volunteers, in the summer of 1964. One former member of the Student Nonviolent Coordinating Committee says that she and her fellow SNCC workers were "young and foolish" -- a mixed blessing -- with regard to their limited sense of the dangers involved. Three civil rights workers were brutally murdered, including Michael Schwerner, whose widow, Rita Schwerner Bender, is interviewed in the film.

Nelson's excellent archival material includes snippets of a phone conversation between J. Edgar Hoover and then-president Lyndon B. Johnson, the latter calling Schwerner Bender "very ugly" and "worse than a communist." To say that LBJ doesn't come off well in "Freedom Summer" would be an understatement; indeed, the film shows that the president contrived to keep the live testimony of charismatic Mississippi organizer Fannie Lou Hamer off the networks' televised coverage of the Democratic National Convention. The docu concludes by noting that, a year later, Johnson was forced to sign the Voting Rights Act, which abolished literacy tests designed to disenfranchise black voters.

Sharp editing by Aljernon Tunsil helps deliver the film's story with maximum clarity while building tension in its final third. The late Pete Seeger, who performed for SNCC volunteers in 1964, makes one of his final screen appearances, as does civil rights chronicler Tracy Sugarman, who died last year.

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