Whether a tribal court can exercise jurisdiction over nonmembers of the tribe based on off-reservation conduct

In Montana v. United States , 450 U.S. 544 (1981), this Court recognized a general rule against tribal jurisdiction over nonmembers, subject to two narrow exceptions for “non-Indians on their reservations.” Id. at 565. The Court has stressed that both exceptions “permit tribal regulation of nonmember conduct inside the reservation that implicates the tribe’s sovereign interests.” Plains Commerce Bank v. Long Family Land & Cattle Co. , 554 U.S. 316, 332 (2008) (emphasis altered). The Suquamish Tribe sued its off-reservation, nonmember insurers in tribal court, seeking coverage for business losses caused by the COVID-19 pandemic on a theory that federal and state courts have rejected virtually unanimously. The in surers filed this action to prevent the exercise of tribal jurisdiction over their off-reservation conduct. While recognizing that “all relevant conduct occurred off the Reservation,” the Ninth Circuit upheld tribal-court jurisdiction over the insurers, reasoning that their conduct “relate[d] to tribal lands” because the insurance policies covered tribal businesses on tribal land. App., infra , 14a-16a. That decision made the Ninth Circuit “the first and only circuit court to extend tribal court jurisdiction over a nonmember withou t requiring the nonmember’s actual physical activity on tribal lands.” Id. at 73a (Bumatay, J., dissenting from denial of rehearing en banc). The question presented is whether a tribal court can exercise jurisdiction ov er nonmembers of the tribe based on off-reservation conduct.