This Time Magazine article indicates that government wiretapping without a warrant is almost as old as the telephone itself. The only things that have changed are the size of government, and the sheer volume of citizen communication conducted via “tappable” technology.
Here are some excerpts from the article:
Wiretapping first became a tool of U.S. law enforcement in the 1890s, but the Supreme Court didn’t establish its constitutionality until 1928, at the height of Prohibition. Roy Olmstead, a Seattle bootlegger, had been convicted on evidence gathered through a wiretap in his home. He argued that authorities had violated his rights–but the court upheld his conviction, saying eavesdropping was not a physical invasion of privacy.
Richard Nixon approved the illegal wiretapping of four reporters and 13 government officials in 1969 in a bid to unmask those leaking information to the press. And in 1972 a grand jury indicted two Nixon aides for the burglary and illegal wiretapping of the Democratic National Committee headquarters at the Watergate Hotel.
Here is a timeline of the history of wiretapping on NPR’s website.