Mapp v. Ohio
A landmark Supreme Court decision, Mapp v. Ohio, 367 U.S. 643, 81 S. Ct. 1684, 6 L. Ed. 2d 1081 (1961), established the rule that evidence that has been obtained by an illegal SEARCH AND SEIZURE cannot be used to prove the guilt of a defendant at a state criminal trial.
Police officers went to the home of Dollree Mapp in an attempt to find someone who was wanted for questioning about a recent bombing. When they demanded entrance to the house, Mapp called her attorney and refused to allow the police to enter without a SEARCH WARRANT. Subsequently the police officers became rough with Mapp and handcuffed her. Upon a search of the house, they found obscene books, pictures, and photographs for the possession of which the defendant was subsequently prosecuted and convicted.
The defendant brought an unsuccessful action challenging the constitutionality of the search. An appeal was made to the Ohio Supreme Court, which affirmed the judgment. The defendant appealed to the U.S. Supreme Court, which reversed the decision on the ground that evidence obtained by an unconstitutional seizure was inadmissible.
The Court was extremely critical of the actions of the police and held that the defendant's privacy had been unconstitutionally invaded. The police tactics were deemed comparable to a confession forced out of a fearful prisoner. The Court ruled that to compel respect for the constitutional right of the people to be secure in their persons, houses, papers, and effects against unreasonable searches and seizures, it was necessary to exclude illegally obtained evidence from the consideration of the trial court.
The Supreme Court had ruled, as early as 1886, that any illegally obtained evidence could not be introduced in federal courts. This principle, known as the EXCLUSIONARY RULE, was initially applied to state criminal prosecutions in Mapp. The Court made note of the fact that, in other instances, various states had attempted to prevent illegal police searches by other means, but the exclusionary rule is, in the opinion of the Supreme Court, the only effective means of protecting citizens from illegal searches conducted by government agents.