In this landmark decision, the Supreme Court held that the exclusionary rule was binding on the states whenever evidence was obtained in an unreasonable search and seizure, thereby completing the “incorporation” of the Fourth Amendment into the due process clause of the Fourteenth Amendment.
In an earlier landmark case, Weeks v. United States
Justice Charles Whittaker was among the justices who dissented in Mapp because they objected to applying the incorporation doctrine.
In another landmark case, Wolf v. Colorado
Seven police officers, claiming to have a warrant but never showing it, broke into the home of Dolly Mapp in Cleveland, Ohio. An informant had told them that they would find gambling paraphernalia and a fugitive wanted for a recent bombing. Although they found neither, they did find pornographic books and magazines. These items were used as evidence to convict Mapp of possessing illegal pornographic materials. Ohio’s high court concluded that the incriminating evidence had been obtained illegally, but while referring to Wolf, it nevertheless allowed the evidence to be used. When the case was appealed to the U.S. Supreme Court, an amicus brief of the American Civil Liberties Union advocated that Wolf be overturned, although Mapp’s attorney argued the case entirely on the issue of obscenity.
The majority of the justices decided to ignore the less important obscenity question. Five justices agreed that the exclusionary rule should be applied to the states. Speaking for the five, Justice Tom C. Clark
Clark, Tom C.
Due process, procedural
Douglas, William O.
Ferguson v. City of Charleston
Hudson v. Michigan
Search warrant requirement