However, Indian tribes lost some of that authority by "ceding their lands to the United States and announcing their dependence on the Federal Government." Accordingly, in Oliphant v. Suquamish , the Supreme Court held that Indian tribes do not have inherent sovereign authority to try non-Indian criminal defendants, and in Montana v. United States, the Supreme Court announced the general rule for civil jurisdiction that "the inherent sovereign powers of an Indian tribe do not extend to the activities of nonmembers of the tribe." Tribes may also exercise jurisdiction over nonmembers when Congress authorizes them to do so. Tribal criminal jurisdiction over nonmember Indians is more difficult to discern. Thus, it is not enough that the nonmember have a consensual relationship with a tribe or a tribal member. Threat to the Tribe's Integrity

The second Montana exception provides that tribes may exercise jurisdiction over nonmembers when the nonmember's conduct "threatens or has some direct effect on the political integrity, the economic security, or the health or welfare of the tribe." It is not clear, however, if the power to exclude is independent of the Montana exceptions. Statutory Exceptions

In addition to exercising authority over nonmembers pursuant to their inherent sovereign authority, Indian tribes may exercise jurisdiction over nonmembers within reservations when Congress authorizes them to do so. Nonmembers Must First Challenge Tribal Court Jurisdiction in Tribal Court

Although tribal civil jurisdiction over nonmembers is quite limited, a nonmember defendant in tribal court who believes the court lacks jurisdiction must first challenge the tribal court's jurisdiction in tribal court. However, there are exceptions. First, Congress re-vested Indian tribes with inherent authority to exercise criminal jurisdiction over nonmember Indians, as well as non-Indians who commit dating and domestic violence against Indians within the tribes' jurisdictions, provided the non-Indian has certain enumerated ties to the tribes. Second, under the first Montana exception, tribes may exercise civil jurisdiction over nonmembers when the nonmembers have entered private consensual relationships with the tribe or its members, provided the conduct at issue relates to the consensual relationship. Fourth, tribes may exercise jurisdiction over nonmembers when Congress authorizes them to do so.
Indian tribes are quasi-sovereign entities that enjoy all the sovereign powers that are not divested by Congress or inconsistent with the tribes' dependence on the United States. As a general rule, this means that Indian tribes cannot exercise criminal or civil jurisdiction over nonmembers. There are two exceptions to this rule for criminal jurisdiction. First, tribes may exercise criminal jurisdiction over nonmember Indians. Second, tribes may try non-Indians who commit dating and domestic violence crimes against Indians within the tribes' jurisdictions provided the non-Indians have sufficient ties to the tribes. There are three exceptions to this rule for civil jurisdiction. First, tribes may exercise jurisdiction over nonmembers who enter consensual relationships with the tribe or its members. Second, tribes may exercise jurisdiction over nonmembers within a reservation when the nonmember's conduct threatens or has some direct effect on the political integrity, the economic security, or the health or welfare of the tribe. These first two exceptions, enunciated in the case of Montana v. United States, are based on the tribes' inherent sovereignty, and exercises of jurisdiction under them must relate to a tribe's right to self-government. Third, Indian tribes may exercise jurisdiction over nonmembers when Congress authorizes them to do so. Congress may delegate federal authority to the tribes, or re-vest the tribes with inherent sovereign authority that they had lost previously. Indian tribes may also exercise jurisdiction over nonmembers under their power to exclude persons from tribal property. However, it is not clear whether the power to exclude is independent of the Montana exceptions.
The question of a tribe's jurisdiction over nonmembers can be very complex. It is fair to say, however, that tribal jurisdiction over non-Indians is quite limited. Tribal jurisdiction over nonmember Indians is more extensive. Federal courts, however, consistently require nonmember defendants to challenge tribal court jurisdiction in tribal court before pursuing relief in federal court.