I recall somewhere around the late 80s, there was a federal department that claimed it could listen into one half of all phone calls in the US at a time.
And, iirc, from the ‘30s onward, the FBI kept agents or trained assets in all comms hubs that dealt with overseas communications originating from the US. Except privately owned shortwave. And even that was listened into by agents or assets using scanners.
The entire AT&T system was designed so the government could listen in at anytime they wanted.
“wiretaps” were child’s play
the “wiretap” was built into the phone switches since the 60’s
Now we have the internet and smart phones, instead of hardware, now they just need software, easier and cheaper. Plus you can get pics of the subject, GPS cords, etc as well
During the war when my mother was a child my grandmother (an immigrant from Germany) took in a boarder. After about three weeks he let her know that he was an FBI agent and she had passed the test.