While it is permissible to set up roadblocks on state roads, it can only be to the extent that the stop is limited to determine if the person is an Indian or not. However, the court did clarify that if there are "obvious violations,'' like driving drunk, tribal police officers may detain the person.

Also, because tribal officers act under the authority of state law, they are subject to U.S. constitutional constraints on search and seizure and cannot claim immunity under the principle of tribal sovereignty.

This ruling came out of a recent case where a non-Indian motorist, Terrence Bressi, was stopped by tribal officers at a 2002 Tohono O'odham roadblock on State Route 86, and he alleged that the actions of the officers violated his civil rights.