RIP Dollree Mapp, who's the reason police have to get search warrants

1. Dollree Mapp, the Cleveland woman who successfully checked police power in a landmark US Supreme Court case, died on October 31 at the age of 90 or 91, according to the New York Times.
2. Police tried to enter Mapp's home without a warrant to look for a man wanted for questioning about a bombing. But she challenged the search — and her eventual arrest — in a court case that led to a major Supreme Court decision in 1961.
3. Police arrested Mapp for sexually explicit materials found in the home, and she was sentenced to prison on obscenity charges. But the Supreme Court threw out the conviction, deciding that courts must suppress evidence gathered through police misconduct — in this case, a warrantless search — in certain kinds of cases.

The ruling checked police power at the state level

The US Supreme Court. (Saul Loeb / AFP via Getty Images)

Before the Supreme Court's decision, only federal courts threw out evidence gathered illegally by police. The Supreme Court decision in Mapp v. Ohio cited the Fourth Amendment to extend that rule — known as the exclusionary rule — to state courts, explained the New York Times.

"The state, by admitting evidence unlawfully seized, serves to encourage disobedience to the federal Constitution which it is bound to uphold," Justice Tom Clark wrote in the majority opinion.

The exclusionary rule has been a topic of controversy in legal circles. As a judge, former Justice Benjamin Cardozo said, "The criminal is to go free because the constable has blundered." Former President Ronald Reagan also criticized the rule, claiming that it relies on the "absurd proposition that a law enforcement error, no matter how technical, can be used to justify throwing out an entire case."

Later court rulings carved exceptions to the rule — particularly in cases in which police made errors while acting in good faith, receiving incorrect legal guidance, or relying on bad information from another agency.

Some legal watchers worry the rule could be further watered down or even abolished by the current Supreme Court. Chief Justice John Roberts worked under the Reagan administration to undermine the exclusionary rule, according to the Times.

But for now, the exclusionary rule remains a key check on police misconduct — and Americans have Mapp's belligerence, as police called her behavior at the time, to thank for that.

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