Well, while the NSA and all the other three letter agencies probably mean well, it causes a hell of mess when they are given too free reins and not enough congressional / civil insight. And no, the executive branch alone is not enough. I am currently reading The Untold History of the United States by Oliver Stone and Peter Kuznick, and it is ripe with examples from the cold war years of what can happen..
Anyways, around here the constitution is above all other law, agreements or whatever NDAs you can cook up. So if you need to break some laws or contracts to reveal/stop activity that violates the constitution that would be OK. And I think that is a healthy, non-nonsense approach.