I have complete confidence in Secret Service. These guys and gals are unbelievably professional. They know what they’re doing and I basically do what they tell me to do. Now, sometimes I’m the first one to admit that it chafes a little bit being inside this bubble. It’s the hardest adjustment of being president, not being able to just take a walk.
As long as you don't fly openly in the face of society, society doesn't ask any inconvenient questions; and it makes precious short work of the cads who do. There are no secrets better kept than the secrets everybody guesses.
Science ... looks skeptically at all claims to knowledge, old and new. It teaches not blind obedience to those in authority but to vigorous debate, and in many respects that's the secret of its success.
It's hard to have that debate around secret programs authorized by secret legal opinions issued by a secret court. Actually, it's impossible to have that debate.