United States v. Cooley

In United States v. Cooley, a Crow Tribe police officer detained and searched a non-Indian driver, Joshua James Cooley, on a public highway within the Crow Reservation in Montana, discovering weapons and drugs. Cooley moved to suppress the evidence, arguing tribal officers lack authority over non-Indians. The district court granted the motion, and the Ninth Circuit affirmed, relying on a precedent that tribal police generally cannot detain non-Indians unless apparent exigent circumstances exist. The Supreme Court reversed unanimously, holding that tribal police officers possess inherent sovereign authority to temporarily detain and search non-Indians on public rights-of-way through reservations if they suspect violations of federal or state law, and to transport them for delivery to state or federal authorities. This power is crucial for protecting reservation health and welfare.

The U.S. Supreme Court ruled unanimously (9-0) on June 1, 2021, reversing the Ninth Circuit. The Court held that tribal governments retain inherent sovereign authority to stop and temporarily detain non-Indian motorists on public rights-of-way through reservations when officers have reasonable suspicion of a criminal violation, thereby allowing the evidence to be admissible.

Whether a tribal police officer has the inherent sovereign authority to temporarily detain and search a non-Indian motorist on a public highway that runs through an Indian reservation based on reasonable suspicion of a crime.

The ruling significantly strengthened tribal law enforcement powers, enabling tribal officers to effectively police public highways traversing reservations to combat drug trafficking and violence that disproportionately affect Native communities. It was hailed as a major victory for tribal sovereignty and public safety, clarifying that tribal governments possess the necessary authority to protect their citizens and territory. The decision addressed critical legal loopholes that had allowed non-Indians to evade accountability for crimes committed on reservation lands, restoring a practical tool for maintaining law and order in Indian Country.