Theoretically the idea is you're supposed to elect trustworthy people with good judgment to the positions that sit on the Senate Intelligence Committee and other persons in the US government who approve the budgets of TS/SCI and similar programs....
Something like the Church committee would be nice every decade or so.
Snowden showed they desperately need some light to shine on them once in a while.
Otherwise intelligence agencies have a historically consistent tendency to get a little too laissez faire with people's right.
NRO is probably the most secretive of all of them, but I'm assuming looking at pictures of Russian tanks and Chinese missile silos all day isn't the most civil-rights threatening thing vs storing billions of peoples emails, text messages, and phone calls like the NSA.
False, though common, misunderstanding of responsibilities. The NRO is the operator/owner of the space asset. The NSA is (one of) the customer getting data from the NRO space asset. (along with many other sources)
Though I would bet good money that a vastly greater percentage of what the NSA does for traffic interception, storage and analysis is related to terrestrial based networks (or terrestrial-to-local wireless like LTE) rather than space based, these days.
Of course not, it does mean that we don't have the ability to know if it is useless or nefarious or not.