Except they do. The NSA has been handing over intel over a decade ago:
> A former federal agent in the northeastern United States who received such tips from SOD described the process. “You’d be told only, ‘Be at a certain truck stop at a certain time and look for a certain vehicle.’ And so we’d alert the state police to find an excuse to stop that vehicle, and then have a drug dog search it,” the agent said. [1]
Sure these were criminals, but who knows how many “undesirables” were prosecuted or targeted for some crime anybody commits?
[1] https://arstechnica.com/tech-policy/2013/08/us-drug-agency-g...
The US gov is acting on intel against its citiczens all the time, regular or not.
Personally, I don't like the right wing groups it's infiltrated, but I still think that is a reasonable example.
For me, more pressingly, there are current investigations going on in Minnesota from the US gov's "Puppetmaster" operation that actively infiltrated and monitored a highly diverse set of anti-ICE groups.
Historically this is nothing new; the US has been infiltrating "anti-government" groups for decades. AIM, the panthers, ELF, ALF, labor unions, MOVE, etc are all easy examples of domestic groups that the US gov has broken at some point or other.
Your position only work if you classify folks such as the Minnesota 15 as "terrorists" or some such. Which, hey, folks like the US Gov try to do. But at that point the point is kind of tautological: if you have "something to hide" then you are a legit target of government sanctioning.
That's not very satisfying to me, but plenty of folks in the US find it to be a just-fine principle.