High Quality Content by WIKIPEDIA articles! In United States v. Sioux Nation of Indians, 448 U.S. 371 (1980) the Supreme Court of the United States held that: 1) The enactment by Congress of a law allowing the Sioux Nation to pursue a claim against the United States that had been previously adjudicated did not violate the doctrine of separation of powers, and 2) the taking of property that was set aside for the use of the tribe required just compensation, including interest.