Mapp v. Ohio in 1961: Summary, Decision & Significance

Instructor: Stephen Benz

Stephen has taught history, journalism, sociology, and political science courses at multiple levels, including the middle school, high school and college levels. He has a JD and a BA in sociology and political science.

Dollree Mapp was convicted in 1957 of possession of pornography. But the Supreme Court overturned her conviction because the police obtained evidence illegally. Mapp v. Ohio used the Fourteenth Amendment to apply the Bill of Rights to state laws as well as federal laws.


Knock, Knock, Knock! It's the police! Open up!

This aggressive pounding might have been the noise that greeted Dollree Mapp on May 23rd, 1957, in Cleveland, Ohio. The police suspected that Mapp was part of a gambling ring and that she had been harboring a bombing suspect. The police wanted to search for evidence inside.

When Mapp opened the door, she demanded a search warrant as per her Fourth Amendment right. When the police produced a paper, Mapp snatched it and stuffed it down her blouse. Such hostile action toward the police caused them to search the apartment vigorously. Although police did not find any gambling equipment, they did find pornography in a locked briefcase - a crime in Cleveland at the time. Interestingly, the brief case wasn't even Mapp's. It belonged to a previous tenant of the apartment. Mapp was arrested.

At the trial, no search warrant was produced authorizing the search. Nonetheless, the Ohio Court ruled that the evidence was permissible in trial despite the lack of a warrant. Mapp was convicted.

On appeal to the Supreme Court, Mapp's lawyer argued that she should not have been arrested because possessing pornography was a 1st amendment right. The American Civil Liberties Union (ACLU) also jumped on the case, filing an amicus brief. An amicus brief means 'friend to the Court.' It is filed by people who wanted to join a side in a case and add an additional argument. The ACLU argued that the conviction was unconstitutional because the police violated the Fourth Amendment by not producing a search warrant. The Supreme Court now had to decide the case.

Mapp was arrested for the possession of pornography. Her conviction was overturned by the Supreme Court.

Previous Cases

Previously, the Supreme Court had ruled that illegally obtained evidence was not permissible in Federal Court (Weeks v. United States). But did the Fourth Amendment apply to the state courts? The Supreme Court had ruled in Wolf v. Colorado that states could use illegally obtained evidence in trials because the Fourth Amendment didn't apply to state courts.


In a close 5-4 decision, the Supreme Court overturned the Mapp conviction for violating both the First Amendment and the

Fourth Amendment. The majority opinion, written by Justice Tom Clark, argued that since the Fourteenth Amendment mandated states to provide due process to all citizens, states had to abide by the Fourth Amendment. Clark argued that although criminals may be freed because of this, protecting the rights of all citizens is more important than convicting a criminal.


Mapp v. Ohio's impact has been to greatly change the way in which law enforcement must comply with rules. Conservatives have criticized the ruling for giving too much freedom to criminals while liberals have argued for its importance in assuring the fundamental rights of citizens.

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