In the 1970 case of Kennerly et al. v. District Court of the Ninth Judicial District of Montana et al., members from the Blackfeet Indian Tribe challenged a state court's jurisdiction over their reservation land, arguing that it violated their tribal sovereignty rights under federal law. The U.S. Supreme Court ruled in favor of the tribe, holding that only federal courts have jurisdiction over crimes committed on reservations by or against Native Americans unless Congress has explicitly granted such authority to state courts - which they had not done so for Montana at this time.

In the dissenting opinion for Kennerly et al. v. District Court of the Ninth Judicial District of Montana, Justice Hugo Black argued that tribal courts should have jurisdiction over civil cases involving Native Americans on reservations, even if one party is not a tribe member. He believed that Congress had given tribes this power through legislation and treaties recognizing their sovereignty. Furthermore, he disagreed with the majority's interpretation of previous court decisions as limiting tribal authority in these matters; instead, he saw them as affirming it. Finally, he warned against undermining tribal self-government by denying tribes' ability to handle their own affairs and resolve disputes within their territories.