Back in the stone ages of phone when you had a Ma Bell supplied phone wired to a red and green pair of wires designated Ring and Tip which would lead to a telephone pole and end up in a Ma Bell phone exchange corresponding to the 1st 3 digits of your phone number. Back then in order to eaves drop on a conversation one would in a clandestine fashion connect a device across the red and green wires. This is wiretapping as depicted in the 1974 Gene Hackman movie The Conversation
Now fast forward a few decades we had the Techno-thriller Enemy of the State again we have Gene Hackman and introduce the world of the Digital and Wireless surveillance. Fast forward to the 21st Century a post 9/11 world. You still have “exchanges” now know as Central Offices as depicted in Robert Redford’s Three Days of the Condor. Now central offices are interconnected using digital “circuits” using the long distance phone carriers such as AT&T. We live in a post Patriot Act world revealed by Edward Snowden as reported by the NY Times, Wired Magazine and the Guardian where agencies such as the NSA and England’s GCSC “plug” into the long distance carriers directly at the AT&T facilities in Conyers Georgia and Denver Colorado and suck up all the bits and ship them off to the NSA Utah complex. So now when Director Clapper denies “Wiretapping” we have to remember a prior incident where he played word games.
Basically nobody “Wiretaps” anymore so we have another Clapper “Least untruthful” answer. We don’t wiretap we conduct Surveillance words mean things.