Opinion of the Court
I
A
The Crow Tribe first inhabited modern-day Montana more than three centuries ago. Montana v. United States, 450 U. S. 544, 547 (1981). The Tribe was nomadic, and its members hunted game for subsistence. J. Medicine Crow, From the Heart of the Crow Country 4–5, 8 (1992). The Bighorn Mountains of southern Montana and northern Wyoming “historically made up both the geographic and the spiritual heart” of the Tribe’s territory. Brief for Crow Tribe of Indians as Amicus Curiae 5.
The westward migration of non-Indians began a new chapter in the Tribe’s history. In 1825, the Tribe signed a treaty of friendship with the United States. Treaty With the Crow Tribe, Aug. 4, 1825, 7 Stat. 266. In 1851, the Federal Government and tribal representatives entered into the Treaty of Fort Laramie, in which the Crow Tribe and other area tribes demarcated their respective lands. Montana, 450 U. S., at 547–548. The Treaty of Fort Laramie specified that “the tribes did not ‘surrender the privilege of hunting, fishing, or passing over’ any of the lands in dispute” by entering the treaty. Id., at 548.
After prospectors struck gold in Idaho and western Montana, a new wave of settlement prompted Congress to initiate further negotiations. See F. Hoxie, Parading Through History 88–90 (1995). Federal negotiators, including Commissioner of Indian Affairs Nathaniel G. Taylor, met with Crow Tribe leaders for this purpose in 1867. Taylor acknowledged that “settlements ha[d] been made” upon the Crow Tribe’s lands and that their “game [was] being driven away.” Institute for the Development of Indian Law, Proceedings of the Great Peace Commission of 1867–1868, p. 86 (1975) (hereinafter Proceedings). He told the assembled tribal leaders that the United States wished to “set apart a tract of [Crow Tribe] country as a home” for the Tribe “forever” and to buy the rest of
