Mapp v. Ohio | 1961
Washington State University
Maryland Law School Professor & Clinical-Law Co-Director
Choose a video from the playlist below
  • Mapp v. Ohio full program
  • Justice Souter on Mapp
  • Book Discussion on Mapp v. Ohio: Guarding Against Unreasonable Searches and Seizures
  • Unwarranted Search and Seizure: U.S. v. Nelson
  • Chief Justice Warren and Bakersfield
  • Book Discussion on Justice for All: Earl Warren
  • Reaction to Mapp
  • Fixing Corruption
  • Changes in Search & Seizure
  • Dollree Mapp's Arrest Documents
Subject: Protecting against unreasonable searches and seizures
Case Decided:
June 19, 1961

Mapp v. Ohio (1961) strengthened the Fourth Amendment protection against unreasonable searches and seizures, making it illegal for evidence obtained without a warrant to be used in a criminal trial in state court. This 5-4 decision is one of several cases decided by the Warren Court in the 1960s that dramatically expanded the rights of criminal defendants.

When Cleveland police searched Dollree Mapp’s home for a suspect in a local bombing, she refused to let them in without a search warrant. A few hours later, more officers arrived and forced their way into Mapp’s home. When one officer held up a piece of paper that he said was a warrant, Ms. Mapp snatched it but lost it in a struggle with the officer. In the course of their search, the police found allegedly obscene literature and photos that Mapp said were not hers. Although no warrant was produced at her trial, she was convicted of possessing pornography. Mapp’s attorney argued that Ohio’s obscenity law was unconstitutionally vague, but it was the ACLU’s “friend of the court” brief that called for the exclusion of evidence seized illegally. In his opinion for the Court, Justice Tom Clark wrote that because it was seized without a warrant, the evidence could not be used in Mapp’s trial. Previously, illegally seized evidence had only been excluded in federal criminal trials. This was the first in a series of decisions impacting protections for criminal defendants.

Key Players
Dollree Mapp

Dollree Mapp was a woman affiliated with the boxing and gambling scene in 1950s Cleveland, Ohio. By refusing to allow police officers to search her home without a warrant, her case launched a due process revolution in American law and policing practices.

Photo courtesy of The Cleveland Press Collection
Justice Tom Clark

Tom Clark (September 23, 1899 – June 13, 1977) was a Texas lawyer, U.S. attorney general, and Supreme Court justice (1949 – 1967). He authored the majority opinion in Mapp, writing that “nothing can destroy a government more quickly than its failure to observe its own laws.”

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