The song heard at the end, when Natives are covering the Feds from the top of the stronghold wall, is one of two songs collectively known as The A.I.M. and Freedom Songs, sung at the end of most powwows to honor The American Indian Movement, on which the movie's Aboriginal Rights Movement is based, and Native rights activist Leonard Peltier, on whom the character Jimmy Looks Twice is based.
In the movie, Val Kilmer plays a character who is 1/4th Sioux. In real life, he is 1/4th Cherokee.
The movie is actually a thinly veiled account of real events that occurred on the Pine Ridge Indian Reservation during the early to mid-Seventies. Exploration for Uranium, disease from irradiated water, the American Indian Movement (AIM) and the "Traditional" Natives fight against the Tribal government "Guardians Of the Oglala Nation (GOON's), and the FBI's assistance to the "Goons" by providing weaponry and other assistance are some of the things that are referred to in the movie that were true and documented by Writer/Director Michael Apted when he was a regular visitor to the Reservation during that time.
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.