New Mexico v. Mescalero Apache Tribe

The Mescalero Apache Tribe (plaintiff) ran a federally approved hunting and fishing program on its reservation, licensing non-Indians to hunt and fish under tribal ordinances. New Mexico (defendant) claimed concurrent jurisdiction to enforce its own state hunting and fishing regulations against those same non-Indians, and began arresting non-Indians who possessed game taken legally under tribal rules but illegally under state law. The Tribe sued to enjoin New Mexico from enforcing state regulations on the reservation, and both the trial and appellate courts ruled for the Tribe.