In the 1967 case Whitney v. Florida, the U.S. Supreme Court upheld a decision by the Florida Supreme Court that denied relief to a man convicted of robbery based on evidence obtained through wiretapping. The petitioner, Whitney, argued that his Fourth Amendment rights had been violated because law enforcement did not have probable cause for their search and seizure of his private communications. However, both courts ruled against him due to an exception in federal law allowing wiretap evidence if it was "essential to the protection of the state's interest." This ruling reinforced states' ability to use wiretap evidence in criminal cases under certain circumstances.

In the dissenting opinion for Whitney v. Florida, Justice Fortas argued that the majority's decision to uphold a state law prohibiting picketing was an infringement on First Amendment rights of free speech and assembly. He contended that peaceful picketing is a form of expression protected by the Constitution, even if it may cause inconvenience or annoyance to some people. The justice further stated that suppressing such activities would set a dangerous precedent where any public demonstration could be deemed illegal simply because it might disturb others or disrupt business operations. He also criticized the court's reliance on past cases which he believed were not applicable in this context as they involved violent conduct unlike in this case where there was no evidence of violence or threat thereof.