Over a century ago, Alexander Graham Bell invented the telephone and it was soon within widespread use. Not surprisingly, police soon saw the value of listening in on private phone conversations, and wiretapping was born . But in 1933, Congress decided that interceptions of phone calls were an invasion of privacy comparable to a physical search under the Fourth Amendment. So, in order to listen to the content of a telephone call through a wiretap, police must first get a warrant and demonstrate to a judge that there is probable cause to think criminality is afoot.
Read the complete commentary here.