[cryoshon]

The NSA lied to the congressional oversight committee repeatedly and reliably. After each lie, there was another leak which showed them to be liars.

They tried to hide by redefining the meaning of all sorts of simple terms ("collection" comes to mind) and narrow political answers like "not under this program".

There hasn't been any actual overview by either party... the actions of the NSA are aggressively hidden from them, and they prosecute whistleblowers.