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Case Basics
Docket No. 
Dollree Mapp
(Argued the cause for the appellant)
(Argued the cause for the American Civil Liberties Union et al., as amici curiae, urging reversal)
(Argued the cause for the appellee)
Facts of the Case 

Dollree Mapp was convicted of possessing obscene materials after an admittedly illegal police search of her home for a fugitive. She appealed her conviction on the basis of freedom of expression.


Were the confiscated materials protected by the First Amendment? (May evidence obtained through a search in violation of the Fourth Amendment be admitted in a state criminal proceeding?)

Decision: 6 votes for Mapp, 3 vote(s) against
Legal provision: Amendment 4: Fourth Amendment

The Court brushed aside the First Amendment issue and declared that "all evidence obtained by searches and seizures in violation of the Constitution is, by [the Fourth Amendment], inadmissible in a state court." Mapp had been convicted on the basis of illegally obtained evidence. This was an historic -- and controversial -- decision. It placed the requirement of excluding illegally obtained evidence from court at all levels of the government. The decision launched the Court on a troubled course of determining how and when to apply the exclusionary rule.

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MAPP v. OHIO. The Oyez Project at IIT Chicago-Kent College of Law. 02 September 2015. <>.
MAPP v. OHIO, The Oyez Project at IIT Chicago-Kent College of Law, (last visited September 2, 2015).
"MAPP v. OHIO," The Oyez Project at IIT Chicago-Kent College of Law, accessed September 2, 2015,