United States v. Sioux Nation of Indians, 448 U.S. 371 (1980), was a United States Supreme Court case in which the Court 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 in the Black Hill region of South Dakota which had been set aside for the use of the tribe required just compensation, including interest. The Sioux have not accepted the financial compensation awarded to them by this case, valued at over $2 billion as of 2022, and have insisted on regaining control of the land.

Facts of the case The Treaty of Fort Laramie (1868) pledged that the Great Sioux Reservation, including the Black Hills, would be "set apart for the absolute and undisturbed use and occupation of the Indians." ("US v Sioux Nation"). By the terms of the treaty, cession of any part of the reservation required a new treaty executed and signed by at least three fourths of all the adult male Indians occupying the land.US v Sioux Nation 448 US 371 at 376–77. The Sioux's right to hunt in some unceded territories were protected by the Fort Laramie Treaty as well. The Fort Laramie Treaty ended Red Cloud's War, a series of military engagements in which the Sioux tribes, led by chief Red Cloud, fought to protect the integrity of earlier-recognized treaty lands from the incursion of white settlers.US v Sioux Nation, 448 U.S. 371, 374.

The 1868 treaty brought peace for a few years, but in 1874 an exploratory expedition under General George A. Custer entered the Black Hills to investigate rumors of gold. "Custer's florid descriptions of the mineral and timber resources of the Black Hills, and the land's suitability for grazing and cultivation... received wide circulation, and had the effect of creating an intense popular demand for the 'opening' of the Hills for settlement.""US v Sioux Nation" 448 US 371 at 377. Initially the U.S. military tried to turn away trespassing miners and settlers. Eventually, however, President Grant, the Secretary of the Interior, and the Secretary of War "decided that the military should make no further resistance to the occupation of the Black Hills by miners." These orders were to be enforced "quietly" and the President's decision was to remain "confidential"."US v Sioux Nation" 448 US 371 at 378.

As more and more settlers and gold miners invaded the Black Hills, the government concluded that the only practical course was to take the land from the Sioux, and appointed a commission to negotiate the purchase."US v Sioux Nation" 448 US 371 at 379. The negotiations failed, and so the US resorted to military force. They used as a pretext to declare the Sioux Indians "hostile" their failure to obey an order to return from an off-reservation hunting expedition in the dead of winter when travel was impossible."US v Sioux Nation" 448 US 371 at 379–380. The consequent military expedition to remove the Sioux from the Black Hills included an attack on their village on the Little Bighorn River led by Custer. The attack culminated in the victory of Chiefs Sitting Bull and Crazy Horse over the 7th Cavalry Regiment now known as Battle of the Little Bighorn.'"US v Sioux Nation" 448 US 371 at 379.

That victory was short-lived. Those Indians who survived subsequent battles to surrender to the Army were interned on a reservation and deprived of their weapons and horses, "leaving them completely dependent for survival on rations provided them by the Government." In August 1876, Congress enacted a bill cutting off appropriations "made for the subsistence" of the Sioux unless they ceded the Black Hills to the United States. A commission headed by George Manypenny presented the Sioux with a new treaty and they signed, under threat of starvation."US v Sioux Nation" 448 US 371 at 381. Only a few leaders signed, not the 3/4 majority of all Indian males on the reservation as required under the Fort Laramie Treaty."US v Sioux Nation" 448 US 371 at 382.

S. 590 (1876) After the "Army's withdrawal from its role as enforcer of the Fort Laramie Treaty" the previous year and its subsequent return to prepare for a military campaign against the Sioux, a bill was introduced in the U.S. Senate to authorize "a peaceful settlement" with the Sioux Nation for the Black Hills. A proposed "five-member commission" would have asked the Sioux Nation to relinquish the "entire reservation" given to them under the Fort Laramie Treaty. From most "congressional and pioneer views" this was the "easy and practical method" of securing the Blacks Hills.

S. 590 was approved by the Senate with a vote of thirty to eight, with language that implied that the commission could acquire the entire reservation and relocate the Sioux. In the House Committee on Indian Affairs, it was amended to specify that "nothing in this bill could be construed or twisted to allow for the removal of the Sioux Nation to Indian Territory." Peace efforts or "attempts to purchase the Blacks hills" could still proceed. Missourians praised the action since it would have kept the Sioux far from their borders.U.S., Congress, Woüse, Journal. 44th Cong., 1st sess., 1875-1876, pp. 1050, 1084; U.S., Congress, House, Committee on Indian Affairs, Index of Reports of Committees of the House of Representatives, H. Rept. 674, 44th Cong, 1st sess 1875-1876 (SeriaH712), p. \, St. Louis Republican. 1 June 1876.

However, after the Battle of the Little Big Horn public opinion turned against the Sioux and Congress refused to address the bill. When asked why, Congressman Omar D. Conger opined that Congress felt the need to "find out whether the Sioux have captured all our army before we go treating with them."House Journal, 44 Cong., 1 sess., 1875-1876, p. 1257; House, Congressional Record, 44 Cong,, 1 sess., 1875-1876, 4, pt. 5:4520

S. 590 went on to die in committee and Congress approved the Indian Appropriations Bill of 1876 instead. It "illegally denied the Sioux all further appropriation and treaty-guaranteed annuities" until they gave up the Black Hills.

20th century litigation of the Sioux claim for the Black Hills

The Sioux never accepted the legitimacy of their forced deprivation of their Black Hills reservation.US v. Sioux Nation, 448 US 371 at 384. In 1920, lobbyists for the Sioux persuaded Congress to authorize a lawsuit against the United States in US Claims Court. The Sioux filed a petition in 1923, but the Claims Court dismissed the case in 1942, holding that the Court could not second guess whether their compensation under the 1877 Agreement reached by the Manypenny Commission – which served as the basis for the 1877 Act of Congress – was adequate.US v. Sioux Nation 448 US 371 at 384. The Sioux (and many other tribes) continued lobbying Congress for a forum for their claims, and in 1946 Congress created an independent federal agency, the Indian Claims Commission, to "hear and determine all tribal grievances" including the Sioux claim.US v. Sioux Nation, 448 US 371 at 385.

The Sioux lost their first hearing before the Indian Claims Commission "due to the failings of their former counsel", but on appeal to the US Claims Court, the Court directed the Commission to take new evidence, which it did in 1958. Then ensued what the US Supreme Court called "a lengthy period of procedural sparring" from 1958 until 1972 – when the Commission ruled in favor of the Sioux, awarding damages for the deprivation of the land, but not interest. On appeal the Government did not contest the Commission's holding that it had "acquired the Black Hills through a course of unfair and dishonorable dealing for which the Sioux were entitled to damages."US v. Sioux Nation, 448 US 371 at 387. In effect, the Government was disputing only whether the Sioux could collect 100 years' worth of interest. The Claims Court ruled that its previous 1942 dismissal of the Sioux’s Fifth Amendment Taking case was (a case already decided), "whether rightly or wrongly", thus denying the opportunity to seek 100 years' worth of interest.US v. Sioux Nation, 448 US 371 at 388.

The case returned to the Indian Claims Commission to determine minor leftover issues about the value of rights-of-way and government offsets. In the meantime, in 1978 the Sioux lobbyists persuaded Congress to pass yet another law conferring authority on the Claims Court to hear the Sioux case, this time without regard to . That meant the Sioux could re-litigate the claim as a Fifth Amendment Taking, to collect 100 years' worth of interest. Finally, under its new authorizing statute, the Claims Court held the Sioux had suffered a Taking cognizable under the Fifth Amendment, and were entitled to the value of the land as of the 1877 taking which was $17.1 million, the value of gold prospectors illegally took out of the land computed at $450,000, and 100 years' worth of interest at 5% per year which would be an additional $88 million.US v. Sioux Nation, 448 US 371 at 390, footnote 16.

This Government appealed this decision, and the US Supreme Court granted its petition for certiorari.

Supreme Court decision Justice Blackmun delivered the Court's opinion in which six other justices joined. Justice White concurred in part, and Justice Rehnquist dissented.U.S. v. Sioux Nation, 448 U.S. at 373.

The issue was whether the Sioux had already received just compensation for their land, and the Court affirmed the Claims Court's decision that they never had.U.S. v. Sioux Nation, 448 U.S. at 420–21. The Court recognized a tension between Congress's duty to serve as a benevolent trustee for Indians, and the power to take their land.U.S. v. Sioux Nation, 448 U.S. at 408–09. "Congress can own two hats, but it cannot wear them both at the same time," said the opinion.U.S. v. Sioux Nation, 448 U.S. at 408. While reaffirming earlier decisions that Congress has "paramount authority over the property of the Indians," the Court concluded that Congress acts properly only if it "makes a good faith effort to give the Indians the full value of the land," which here it had failed to do.U.S. v. Sioux Nation, 448 U.S. at 409. In conclusion the Supreme Court ordered "just compensation to the Sioux Nation, and that obligation, including an award of interest, must now, at last, be paid."U.S. v. Sioux Nation, 448 U.S. at 423.

Dissent

Associate Justice William Rehnquist was the lone dissenter in this case. Rehnquist felt Congress overstepped the bounds of separation of powers by intruding upon the finality of a judicial decision when it "reviewed a prior decision of an Art. III court,A federal court established under Article III of the U.S. Constitution. The Claims Court was not an Article III court at the time it decided the Sioux case in 1942, but became one in 1953 before the 1970s decisions. eviscerated the finality of that judgment, and ordered a new trial in a pending case."'"US v Sioux Nation" 448 US 371 at 434. Rehnquist also disagreed that the initial Court of Claims decision in 1942 was wrong. He endorsed the view that the Sioux already had been adequately compensated for their land.'"US v Sioux Nation" 448 US 371 at 434–35. Rehnquist's dissent suggests that it is "quite unfair to judge by the light of 'revisionist' historians or the mores of another era actions that were taken under pressure of time more than a century ago.""US v Sioux Nation" 448 US 371 at 435.

Response to the decision The Sioux have declined to accept the money, because acceptance would legally terminate Sioux demands for return of the Black Hills. The money remains in a Bureau of Indian Affairs account accruing compound interest. , the Sioux's award plus interest was "about $1 billion" or "1.3 billion" (equivalent to $ to $ billion in ).