"You are also asked to take an oath, and that's the oath of service. The oath of service is not to secrecy, but to the Constitution - to protect it against all enemies, foreign and domestic. That's the oath that I kept, that James Clapper and former NSA director Keith Alexander did not. You raise your hand and you take the oath in your class when you are on board. All government officials are made to do it who work for the intelligence agencies - at least, that's where I took the oath."