It’s only in the 1920s that ordinary Americans start to take notice of wiretapping and it’s not really until the 1950s that it’s seen as a national problem. Even then, it’s mostly the issue of private wiretapping that concerns people. Wiretapping for hire was extremely common in certain locations, most famously in New York. It was legal, for instance, under murky one-party consent laws to hire an electronic surveillance specialist—known as a “private ear”—to tap your wires to see if your wife is carrying on with another man. Needless to say, the American public was worried about this army of unofficial actors who had the ability and the know-how to tap into the rapidly expanding telephone network.
Feelings were mixed about “official” wiretapping. By 1965, the normative political position in the United States was that wiretapping for national security was a necessary evil, whereas wiretapping in the service of the enforcement of criminal law—in, say, tax evasion cases or even in Mafia prosecutions, which was a big priority among American law enforcement starting in the 1960s—was outrageous and an abuse of power.