imminent lawless action and is likely to incite or produce such action." In 1962, Engel v. Vitale held that the Establishment Clause prohibits mandatory prayer in public school. The ruling sparked a strong backlash from many political and religious leaders, some of whom called for the impeachment of Warren. Warren became a favored target of right-wing groups, such as the John Birch Society, as well as the 1964 Republican presidential nominee, Barry Goldwater. Engel, the criminal procedure cases, and the persistent criticism of conservative politicians like Goldwater and Nixon contributed to a decline in the Court's popularity in the mid- and the late 1960s. Griswold v. Connecticut had the Court strike down a state law designed to restrict access to contraception, and it established a constitutional right to privacy. Griswold later provided an important precedent for the case of Roe v. Wade, which disallowed many laws designed to restrict access to abortion. Criminal procedure In the early 1960s, the Court increasingly turned its attention to criminal procedure, which had traditionally been primarily a domain of the states. In Elkins v. United States (1960), Warren joined with the majority in striking down the "Silver Platter Doctrine," a loophole to the exclusionary rule that had allowed federal officials to use evidence that had been illegally gathered by state officials. The next year, in Mapp v. Ohio, the Court held that the Fourth Amendment's prohibition on "unreasonable searches and seizures" applied to state officials. Warren wrote the majority opinion in Terry v. Ohio (1968) in which the Court established that police officers may frisk a criminal suspect if they have a reasonable suspicion that the suspect is committing or is about to commit a crime. In Gideon v. Wainwright (1962), the Court held that the Sixth Amendment required states to furnish publicly-funded attorneys to all criminal defendants accused of a felony and unable to afford counsel. Prior to Gideon, criminal defendants had been guaranteed the right to counsel only in federal trials and capital cases. In Escobedo v. Illinois (1964), the Court held that the Sixth Amendment guarantees criminal suspects the right to speak to their counsel during police interrogations. Escobedo was limited to criminal suspects who had an attorney at the time of their arrest and requested to speak with that counsel. In the landmark case of Miranda v. Arizona, Warren wrote the majority opinion, which established a right to counsel for