Cooley’s truck, parked on the side of a US highway running through the Crow Reservation in Montana, attracted the attention of a Crow Police Department officer. The officer said that when he approached the truck, he found Cooley “appeared to be non-native” and showed signs of intoxication; he also had two semiautomatic rifles on his front seat. The officer eventually ordered Cooley out of the truck and patted him down; eventually he would discover methamphetamine and paraphernalia in the vehicle.
Tribal officers have limited powers in dealing with non-Indians on reservation lands. The Ninth Circuit held that the officer’s detention of Cooley had exceeded his authority and suppressed the evidence he uncovered. That court believed that the officer was obligated to determine whether Cooley was non-Indian and, if so, could detain him only if his violation of state or federal law was “apparent.”
The Supreme Court disagrees. The unanimous opinion here quotes Montana v. United States, 450 U. S. 544, 566 (1981), saying that a “tribe may … retain inherent power to exercise civil authority over the conduct of non-Indians … within its reservation when that conduct threatens or has some direct effect on the political integrity, the economic security, or the health or welfare of the tribe.” It goes on that “To deny a tribal police officer authority to search and detain for a reasonable time any person he or she believes may commit or has committed a crime would make it difficult for tribes to protect themselves against ongoing threats. ” Slip op. at 4.
The Court’s legal discussion is about tribal sovereignty and what limits Congress may have placed upon it. Missing is an explicit connection to the usual terms by which we assess police searches and seizures, so it’s not perfectly clear what it means for a tribal officer to detain someone for a “reasonable time” nor what it means to say the officer “believes” the person has committed a crime. Justice Alito, concurring alone and in a single paragraph, tries to recast the case in traditional Fourth Amendment language (“reasonable suspicion”). He would also specify that the detention can last only so long as “reasonably necessary for a non-tribal officer to arrive on the scene.” That this is a one-justice concurrence serves to point up the murkiness of the unanimous holding.