Background & Facts
The Crow Tribe enacted regulations prohibiting non-members from hunting and fishing within the boundaries of the Crow Reservation, including on portions of the Big Horn River that flowed through fee-patented land owned by non-Indians. The State of Montana asserted concurrent regulatory authority. The United States sued Montana on behalf of the Tribe.
The case asked the Supreme Court to decide whether the Tribe could regulate non-members on land within reservation boundaries that had passed out of tribal ownership into non-Indian fee title.
The Court split the question in two — and in doing so, it created the framework that has governed every tribal civil-jurisdiction case since.
The Court's Holding — The Montana Framework
The Court announced a general rule with two important exceptions. The general rule is that tribes lack civil regulatory authority over non-members on non-Indian fee land within a reservation. But that rule yields when one of the two "Montana exceptions" applies.
General Rule:
Tribes generally lack civil jurisdiction over non-members on fee land — UNLESS one of the two Montana exceptions applies.
Exception 1 — Consensual Relationships:
"A tribe may regulate, through taxation, licensing, or other means, the activities of nonmembers who enter consensual relationships with the tribe or its members, through commercial dealing, contracts, leases, or other arrangements."
Exception 2 — Direct Effects on Tribe:
"A tribe may also retain inherent power to exercise civil authority over 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 or welfare of the tribe."
Key Language
"Indian tribes retain inherent sovereign power to exercise some forms of civil jurisdiction over non-Indians on their reservations, even on non-Indian fee lands."
"The exercise of tribal power beyond what is necessary to protect tribal self-government or to control internal relations is inconsistent with the dependent status of the tribes, and so cannot survive without express congressional delegation."
"Through their original incorporation into the United States as well as through specific treaties and statutes, the Indian tribes have lost many of the attributes of sovereignty."
How ATN Uses Montana
Montana is the framework that runs every tribal civil case in 2026. The general rule sounds limiting — but the two exceptions are wide enough that tribes have built robust civil jurisdiction over non-Indians on commercial, environmental, and public-safety matters. ATN's tribal court will live and breathe inside the Montana exceptions.
Practical applications for ATN's Mendocino jurisdiction:
- 1. Commercial counterparties (Exception 1). Any non-Indian business that signs a contract with ATN, leases ATN land, buys an ATN cannabis license, performs construction on the reservation, or insures tribal property has entered a "consensual relationship." Disputes go to tribal court. Lexington v. Smith (9th Cir. 2024) applies this exception in ATN's circuit and is now settled law after cert was denied in May 2025.
- 2. Environmental and resource conduct (Exception 2). Non-Indian conduct that threatens water quality, fisheries, forest health, or other tribal resources falls within Exception 2. Mendocino's coastal and timber resources give ATN a strong factual basis for invoking this prong.
- 3. Public-health regulation. Conduct on or affecting the reservation that threatens tribal health or welfare — illegal grows, unsafe operations, environmental contamination — falls within Exception 2's "health or welfare" clause.
- 4. Trust land is different. The Montana general rule applies only to non-Indian fee land. On tribal trust land (the core of the Mendocino Indian Reservation), tribal civil authority is at its strongest. Montana actually strengthens ATN's position on trust land by isolating the limiting rule to fee parcels.
- 5. PL280 does not displace Montana. PL280 added state adjudicatory authority. It did not extinguish tribal civil jurisdiction. Under Montana, tribal civil authority over non-members on commercial and conduct-based grounds is concurrent with whatever PL280 conferred on California.
Montana is not the ceiling — it is the doorway. Once a non-member walks through it (by contracting with the tribe, conducting business on or near tribal land, or affecting tribal resources), tribal jurisdiction follows them in.
Related Cases
- Lexington Insurance Co. v. Smith (9th Cir. 2024) — Modern application of Montana Exception 1 in California; cert denied
- Oliphant v. Suquamish (1978) — The criminal-jurisdiction analogue Montana works around
- Walker v. Rushing (8th Cir. 1990) — Tribes in PL280 states retain concurrent jurisdiction
- White Mountain Apache v. Bracker (1980) — Companion preemption framework for state regulation