Mapp v. Ohio: A Milestone Ruling Against Illegally Obtained Evidence

Key Supreme Court Case in Criminal Procedure

Police officers search for evidence hidden under a mattress
Police Search for Evidence. Mario Villafuerte / Getty Images  

The case of Mapp v. Ohio, decided by the U.S. Supreme Court on June 19, 1961, strengthened the Fourth Amendment protections against unreasonable searches and seizures by making it illegal for evidence obtained by law enforcement without a valid warrant to be used in criminal trials in both federal and state courts. The 6-3 decision was one of several handed down by the Supreme Court during the 1960s under Chief Justice Earl Warren that significantly enhanced the constitutional rights of criminal defendants.

Fast Facts: Mapp v. Ohio

  • Case Argued: March 29, 1961
  • Decision Issued: June 19, 1961
  • Petitioner: Dollree Mapp
  • Respondent: State of Ohio
  • Key Questions: Is “obscene” material protected by the First Amendment, and if such material is obtained by means of an illegal search can it be used as evidence in court?
  • Majority Decision: Justices Warren, Black, Douglas, Clark, Brennan, and Stewart
  • Dissenting: Justices Frankfurter, Harlan, and Whittaker
  • Ruling: The First Amendment issue was deemed irrelevant, however the court ruled that any evidence obtained by searches and seizures in violation of the Fourth Amendment is inadmissible in a state court. 

Prior to Mapp v. Ohio, the Fourth Amendment’s ban against the use of illegally gathered evidence applied only to criminal cases tried in the federal courts. To extend the protection to the state courts, the Supreme Court relied on a well-established legal doctrine known as “selective incorporation,” which holds that the due process of law clause of the Fourteenth Amendment bans the states from enacting laws that might infringe on the rights of American citizens.

The Case Behind Mapp v. Ohio

On May 23, 1957, Cleveland police wanted to search the home of Dollree Mapp, who they believed might be harboring a bombing suspect along with possibly having some illegal betting equipment. When they first came to her door, Mapp did not allow the police to enter stating that they did not have a warrant. A few hours later, the police returned and forced their way into the house. They claimed to have a valid search warrant, but they did not allow Mapp to inspect it. When she grabbed the warrant anyway, they handcuffed her. While they did not find the suspect or the equipment, they did find a trunk containing pornographic materials which violated Ohio law at the time. At the original trial, the court found Mapp guilty and sentenced her to jail despite no evidence of a legal search warrant being presented. Mapp appealed to the Ohio Supreme Court and lost. She then took her case to the U.S. Supreme Court and appealed, arguing that the case was essentially a violation of her First Amendment right to freedom of expression.

The Supreme Court Decision (1961)

The Supreme Court under Chief Justice Earl Warren ended up siding with Mapp in a 6–3 vote. However, they chose to ignore the question of whether a law against the possession of obscene material violated her right to freedom of expression as explained in the First Amendment. Instead, they focused on the Fourth Amendment to the Constitution. In 1914, the Supreme Court had ruled in Weeks v. United States (1914) that illegally obtained evidence could not be used in federal courts. However, the question remained whether this would be extended to state courts. The question was whether Ohio law failed to provide Mapp with her Fourth Amendment protection against "unreasonable searches and seizures." The Court decided that "...all evidence obtained by searches and seizures in violation of the Constitution is, by [the Fourth Amendment], inadmissible in a state court."

Mapp v. Ohio: Exclusionary Rule and 'Fruit of the Poisonous Tree'

The Supreme Court applied the exclusionary rule and "fruit of the poisonous tree" doctrine articulated in Weeks and Silverthorne to the states in Mapp v. Ohio in 1961. It did so by virtue of the incorporation doctrine. As Justice Tom C. Clark wrote: 

Since the Fourth Amendment's right of privacy has been declared enforceable against the States through the Due Process Clause of the Fourteenth, it is enforceable against them by the same sanction of exclusion as is used against the Federal Government. Were it otherwise, then, just as without the Weeks rule the assurance against unreasonable federal searches and seizures would be "a form of words," valueless and undeserving of mention in a perpetual charter of inestimable human liberties, so too, without that rule, the freedom from state invasions of privacy would be so ephemeral and so neatly severed from its conceptual nexus with the freedom from all brutish means of coercing evidence as not to merit this Court's high regard as a freedom "implicit in the concept of ordered liberty."

Today, the exclusionary rule and "fruit of the poisonous tree" doctrine are regarded as basic principles of constitutional law, applicable in all U.S. states and territories.

Significance of Mapp v. Ohio

The Supreme Court decision in Mapp v. Ohio was quite controversial. The requirement for ensuring that evidence was legally obtained was placed on the court. This decision would open up the court to a number of difficult cases concerning how to apply the exclusionary rule. Two major Supreme Court decisions have made exceptions to the rule created in Mapp. In 1984, the Supreme Court under Chief Justice Warren E. Burger created the "inevitable discovery rule" in Nix v. Williams. This rule states that if there is a piece of evidence that would have eventually been discovered through legal means, then it is admissible in a court of law.

In 1984, the Burger Court created the "good faith" exception in U.S. v. Leon. This exception allows evidence to be allowed if a police officer believes that his or her search is, in fact, legal. Thus, the court needs to decide if they acted in "good faith." The court has decided this for instances where there were problems with the search warrant that the officer was not aware of.

Was Boxing Behind It?: Background on Dollree Mapp

Previous to this court case, Mapp had sued boxing champion Archie Moore for breach of promise for not marrying her.

Don King, the future fight promoter for such boxing stars as Muhammad Ali, Larry Holmes, George Foreman, and Mike Tyson, was the target of the bombing and gave the police the name Virgil Ogletree as the possible bomber. That led the police to Dollree Mapp's home, where they believed the suspect was hiding.

In 1970, 13 years after the illegal search that culminated in Mapp v. Ohio, Mapp was convicted of having in her possession $250,000 worth of stolen goods and drugs. She was sent to prison until 1981.

Updated by Robert Longley

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Kelly, Martin. "Mapp v. Ohio: A Milestone Ruling Against Illegally Obtained Evidence." ThoughtCo, Feb. 16, 2021, Kelly, Martin. (2021, February 16). Mapp v. Ohio: A Milestone Ruling Against Illegally Obtained Evidence. Retrieved from Kelly, Martin. "Mapp v. Ohio: A Milestone Ruling Against Illegally Obtained Evidence." ThoughtCo. (accessed June 1, 2023).