Communications Act of 1934

Congress enacted the first federal wiretap statute as a temporary measure to prevent disclosure of government secrets during World War I.

Later, it proscribed intercepting and divulging private radio messages in the Radio Act of 1927, but did not immediately reestablish a federal wiretap prohibition.

By the time of the landmark Supreme Court decision in Olmstead v. United States, 277 U.S. 438 (1928), however, at least forty-one of the forty-eight states had banned wiretapping or forbidden telephone and telegraph employees and officers from disclosing the content of telephone or telegraph messages or both.

In Olmstead, the majority held that the Fourth Amendment’s search and seizure limitations did not apply to government wiretapping accomplished without a trespass onto private property.

In response to that ruling, Congress enacted the 1934 Communications Act by expanding the Radio Act’s proscription against intercepting and divulging radio communications to include intercepting and divulging radio or wire communications.

http://itlaw.wikia.com/wiki/Wiretapping