United States v. Cooley

Background

A Crow tribal police officer stopped Joshua Cooley, a non‑Indian driver, late at night on a public highway that runs through the Crow Reservation. The officer noticed possible signs of impairment and weapons, saw drug paraphernalia in the vehicle, and took Cooley to the tribal station. Federal prosecutors later charged Cooley, but a lower court suppressed the evidence and the Ninth Circuit affirmed, holding tribal officers lacked the authority to investigate non‑apparent violations on reservation rights‑of‑way.

Reasoning

The Court addressed whether tribal officers may temporarily detain and search non‑Indians traveling on public rights‑of‑way across reservations when state or federal law may have been violated. Relying on its earlier Montana decision, the Court concluded tribes retain inherent authority to police conduct that threatens tribal health or welfare. The Court held that this exception covers a tribal officer’s limited authority to detain, search as needed before transport, and turn over a non‑Indian suspect to state or federal authorities. The Court rejected the Ninth Circuit’s rule requiring officers first to determine a person’s Indian status or that a violation be “apparent,” finding that rule unworkable.

Real world impact

The decision permits tribal police patrolling reservation highways to investigate suspected drug, weapons, or dangerous driving offenses involving non‑Indian travelers and to search or detain briefly for public‑safety reasons. It does not subject non‑Indians to tribal criminal trials; suspects are to be handed to state or federal authorities for prosecution. The Court vacated the Ninth Circuit ruling and sent the case back for further proceedings.

Dissents or concurrances

Justice Alito’s concurrence narrows the holding: stops require reasonable suspicion, searches are limited to safety needs, and detention beyond that needs probable cause while waiting for non‑tribal officers.