Montana V. U.S.

In a 1959 case, Williams v. Lee, the Court had noted that tribal courts have exclusive jurisdiction over claims that arise in Indian country (as defined by statute) that implicate Indian interests. In Montana, however, in a case involving the Crow Tribe, the Court held that the Tribe lacked inherent authority to preclude fishing by nonmembers on waterways within the reservation in which the tribe did not hold the beneficial interest to the underlying land. It found no clear treaty or statutory right to regulate nonmember conduct on fee lands.

The Court also set forth two exceptions to the general rule that tribes lack regulatory authority over non-Indians on non-Indian fee land within the reservation.

• First, it stated that “the tribe may regulate . . . the activities of nonmembers who enter consensual relationships with the tribe or its members.”
• Second, it stated that tribes may regulate “the conduct of non-Indians on fee lands within its reservation when that conduct threatens or has some direct effect on the political integrity, the economic security, or the health and welfare of the tribe.”

Where the “Montana test” is satisfied, a tribe may exercise authority over non-Indians on fee land within the reservation. The test also governs when U.S. may authorize tribes to regulate non-Indian fee lands within reservations under the Clean Water Act. The Court later applied the Montana standard to tribal civil adjudicatory authority in Strate v. A-1 Contractors.