In McGirt v. Oklahoma, the U.S. Supreme Court found that the boundaries of the Muscogee (Creek) Nation, which were set in 1866 and which encompass a large swath of present-day Oklahoma, remain intact. Although non-Indigenous people had settled on the land in droves by the early twentieth century, the Court held that the land remains “Indian Country” until Congress explicitly indicates otherwise. Because Congress never so indicated, the reservation is undiminished.

McGirt marked a massive shift in the Court’s approach to the question of whether reservation boundaries remain in force; demographic history had previously figured prominently in the Court’s rulings in this arena. The Court has relied on similar historical evidence to inform its analysis of a closely related set of questions: those pertaining to whether Indigenous nations’ sovereign powers over their reservations extend to non-Indigenous people. This Note argues that McGirt’s repudiation of a context-driven inquiry in the former line of cases has ramifications for the latter. In particular, this Note argues that the types of evidence and the modes of reasoning that McGirt rejects have been central to the Court’s doctrine of “implicit divestiture,” which holds that Indigenous nations have limited authority over non-Indigenous people on reservations. This Note argues that McGirt and implicit divestiture are incompatible.

This Note concludes that the Court, having undermined its theory of implicit divestiture, should apply McGirt’s mode of analysis to questions involving Indigenous nations’ territorial authority over reservations.