John Trudell (Jimmy Looks Twice) really did serve in Vietnam and was acting chairman of A.I.M. From 1973 to 1979.
During the early to mid-Seventies, there were fifty-seven unsolved murders on the Pine Ridge Indian Reservation due to the fighting between the "Traditionals" and Tribal government sanctioned "goons". This made the Village of Pine Ridge (Pop. 1100) the "Murder Capitol of the Nation" with the highest number of violent death per capita in the United States.
Based on a true story, documented as Incident at Oglala (1992), which was also directed by Michael Apted.
In the movie, Val Kilmer plays a character who is 1/4th Sioux. In real life, he is 1/8th Cherokee (he said that his father's grandmother was Cherokee).
The video clip which William Dawes shows Ray Levoi in the beginning of the film is actual footage of Native American activists rioting in Custer, South Dakota. The activists were protesting the change from a white man's charges from murder to second degree manslaughter, in the death of a Native American in Custer. They scuffled with the South Dakota Highway Patrol, set fire to the courthouse, and incurred property damage.