In December 1867, the Sioux were forced to resign to the United States due to their guerilla tactics against white settlers. The US government paid the tribe 1.5 billion dollars in a Washington thrust fund as long as they stayed on their reservation. If they did not, they permitted white settlers to "shoot to kill" any natives that wondered off their reservation. As long as the white settler was in a covered wagon. This law was not overturned until 1999.