Tribal police have the authority to detain non-Natives traveling through reservation land if the officer has a reasonable belief that the suspect violated state or federal law, the Supreme Court ruled last week.

The unanimous ruling overturned lower courts that said a Crow police officer should not have held a nontribal member who was found to have drugs and weapons in his truck, Navajo Times reports.

The Supreme Court said that the lower courts’ rulings would “make it difficult for tribes to protect themselves against ongoing threats.”

Advocates welcomed the ruling that one said addresses “a crucial issue of law enforcement and safety in Indian Country.”

“The Supreme Court got it right, and upheld tribal authority to do the bare minimum of what any police force should be able to do to protect their homeland and the public safety of members of the community,” said Heather Whiteman Runs Him, director of the Tribal Justice Center at the University of Arizona.

Justice Stephen Breyer, who wrote the opinion for the unanimous court, noted, “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,” Breyer wrote.