you mean spying on American citizens without a warrant?
No wait, you’re serious?
Did you not watch the senate testimony? They have illegally spied on millions upon millions of Americans. For things as petty as “I think this girl likes me” or “I’ll show my father in law!”. No punishments much less termination or what you or I would face: jail.
So yeah, that link is a joke. There are no protections against corrupt law enforcement.
They have “legal” cover by some secret document. It’s easier to fool someone than tell them they were fooled.
there is no non-corrupt agency
Of course, if they're traveling to the US, it's much more likely that they're communicating with Americans (e.g. visiting friends). Which means that scrutiny of Americans' conversations, swept up en masse, will dramatically increase.
If that passes, tell your friends not to visit America. Because if they do, then all your conversations with them are totally fair game for secret government review.