Yeah, there are generally two things keeping society in order. Ethical beliefs about right and wrong and fear of punishment from the powers that be for breaking the law. My concern with the NSA is that there is a culture of "the current laws are unduly stifling on our jobs, so us ignoring them is 'required'", coupled with management's belief in same and thus non-interest in prosecuting people that cross the line. Not to mention such prosecution would inevitably be public and thus the program exposed and the public seeing it is being abused. Taken together you have a perfect recipe for safeguards that exist in theory and are utterly ignored in reality, "for the greater good".