In the 1980 case Arizona v. Manypenny, the U.S. Supreme Court ruled that federal law enforcement officers are immune from state prosecution for actions performed within their official duties, even if those actions would be considered criminal under state law. The case arose when a U.S. Border Patrol officer was charged with manslaughter by the State of Arizona after shooting and killing an individual while on duty near the Mexican border in Douglas, Arizona. The Supreme Court held that because he was acting within his authority as a federal officer at the time of incident, he could not be prosecuted by state authorities for performing his federally mandated duties.

In the dissenting opinion for Arizona v. Manypenny, Justice Brennan disagreed with the majority's ruling that federal officers are immune from state tort liability while performing their duties. He argued that this broad interpretation of immunity was inconsistent with previous Supreme Court decisions and could potentially lead to abuses of power by federal officials without any legal recourse for those affected. Furthermore, he contended that such a sweeping grant of immunity undermines principles of federalism by denying states the ability to enforce their own laws within their borders. In his view, unless Congress explicitly grants such immunity, it should not be assumed or inferred simply because an officer is carrying out his or her official duties.