Haven't we been spying on our own citizens since WWII? Or at least since J Edgar Hoover and thr McCarthy era?
Hoover didn't know your shoe size. It's likely that the NSA could find that out in seconds to minutes (and I'm not kidding).
Hoover was an SOB far worse than McCarthy ever could have been but is still revered by many in the intel services. His name still adorns the FBI HQ building and other than accusations of cross dressing, no ones dug in to truly uncover the evil things that man did.
The fact that there were soviet agents in the government is mostly tangential. It was because he went around saying there's a secret list of enemies, and that anyone who is left of center is probably one of them, that he was so horrible. It was because he made disgusting personal attacks and aired the dirty laundry of anyone who crossed him. It was because of his deep hatred for homosexuals and anyone who wasn't right wing.
He was one of the more vile characters in US history. J. Edgar Hoover was much worse, I'll concede; Hoover was actually a traitor, the worst in US history, and should have been jailed or executed. But McCarthy deserves every bit of tarnishing he gets, and a whole lot more that he doesn't get because people have forgotten.