This argument is actually subject to Russel's Teapot, if you cant prove or disprove anything the burden of proof is on proving the thing. I have yet to see any evidence.
We as a society do not have that power, and that should be obvious by now.
When a court decided what they were doing was illegal, less than a day later (probably the fastest anything has EVER happen in the legal system), another bench decided that what the NSA was doing was TOO BIG TO STOP. Like seriously, their argument for not stopping something UNCONSTITUTIONAL was that they were doing too much of it.
You and I, and every other civilian who actually understands what they're doing have ZERO power to stop them, so they have ZERO incentive to convince US what matters.
You know who they DO have to convince? The exact people that keep voting to KEEP THEM IN POWER.
I don't care what Obama and his administration claims, like I said, they have no incentive to prove anything to the American public.
"Is mass surveillance useless? Unless you can prove it, it's obviously useful. See Russell's teapot."
(Russell's teapot doesn't apply anyway, because the thing to prove is falsifiable: governments /could/ release information about thwarted attacks, in case there are any.)