In early 1973, the Oglala were divided: they had impeached their president, to no avail, and his (US) government-backed police force were running roughshod. The American Indian Movement was called in, to assist in actions (protests) calling attention to this situation. The US moved in, perhaps overreacting, and a 72-day siege ensued; the Army ousted the AIM folks. The incident led to the FBI's COINTELPRO treatment, resulting in many AIM deaths and the incarceration of Leonard Peltier.