Electronic Eavesdropping

Supreme Court rulings on the constitutionality of using electronic equipment to conduct surveillance of individuals. The basic questions facing the Court are whether and when electronic surveillance constitutes a violation of the Fourth Amendment guarantee of security against unreasonable search and seizure.

From 1928 until 1967, the Court held firmly that the Fourth Amendment applied only when there was physical entry and seizure; it did not apply to overheard conversations. This rule was set out in Olmstead v. United States (1928). In this case, police used wiretaps to gather evidence against a bootlegging operation. The defendants argued that this method of obtaining evidence violated their Fourth Amendment rights. The Court, with Chief Justice Taft writing its opinion, rejected that claim:

In 1967, the Court forbade electronic surveillance of all types as a violation of the Fourth Amendment. In Katz v. United States (1967), government agents obtained evidence by placing a listening device on the outside of a public telephone booth. The information from the telephone conversations led to the prosecution of individuals involved in illegal bookmaking activities. Justice [Page 105]Potter Stewart explained, “What a person … seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected.” The Court ruled that Katz did not surrender his right to privacy simply because he made calls from a public place.

More recently, the Court in 1986 upheld the use of low-flying aircraft to search fields and backyards for marijuana or narcotics. In 1989, the Court also upheld backyard drug searches by helicopters hovering at four hundred feet. In both instances, police used their own eyes from a public vantage point to look for drugs. “What a person knowingly exposes to the public, even in his home or office, is not a subject of Fourth Amendment protection,” the Court ruled. The justices, however, drew a line at sensing devices that can look into a house. Obtaining by “sense-enhancing technology any information regarding the interior of the home” crosses the line protected by the Fourth Amendment, said Justice Antonin Scalia, writing for a 5-4 majority.