In the 1938 case Minnesota v. United States, the U.S. Supreme Court ruled that a state could not tax Indian reservation lands held in trust by the federal government for Native American tribes or their members. The State of Minnesota had attempted to impose an ad valorem tax on such land owned by Chippewa Indians within its borders, arguing that it was permitted under a 1889 Act of Congress which allowed certain lands to be allotted and sold to tribe members with proceeds going into a trust fund managed by the Secretary of Interior for their benefit. However, this argument was rejected as inconsistent with both treaty obligations and principles of sovereignty; specifically, Justice Hugo Black noted that while Congress has broad powers over Indian affairs including taxation rights if explicitly granted, no such power was conferred here nor can it be implied from ambiguous language in legislation or treaties.

In the dissenting opinion for Minnesota v. United States, Justice McReynolds disagreed with the majority's decision to uphold a conviction based on evidence obtained through an illegal search and seizure. He argued that this violated the Fourth Amendment rights of citizens against unreasonable searches and seizures. Furthermore, he contended that allowing such evidence would encourage law enforcement officers to disregard constitutional protections in their pursuit of criminal convictions. The justice also expressed concern about potential abuses of power by government officials if they were allowed to violate individuals' privacy rights without consequence or oversight from courts.