I think some people get as hung up on their reading of the constitution as others get hung up on the bible. Both seem to be open to interpretation. Luckily, the constitution provided instructions. Like who gets to make laws (Congress), who gets to approve them (President), and who get to decide if they are constitutional (SCOTUS). THAT IS WHAT MAKES THEM LEGAL OR NOT. I imagine that as long as any responsible and many not so responsible people want to challenge our government's right to spying and secrecy, it will end up in the SCOTUS. Even then, they can screw it up aka: Citizens United.
BUT! I'm pretty sure Judge Napolitano is not the final word of exactly what is constitutional. Now, we can argue (and I'm sure we will) about exactly what SHOULD be legal, and then Nappy's OPINION should get just as much press as yours and mine.
Back to Snowden.... I am pretty sure he had to sign a promise to keep our country's secrets when he applied for his clearance. I know I did. Nobody makes you sign that agreement. And he should have been aware that disclosing those secrets was against the law and he would be punished if he did. There is no doubt (he already admitted to it) that he broke the law. If he believes so strongly it was his duty to disclose this information for public dissemination he should have no problem paying the price. In my opinion he is no hero. A hero would not have run away to hide. Nor do we yet know the entirety of what he released. It could be far more damaging.
I am not really comfortable arguing against transparency of information. And in most things I still believe in it. I am old enough to remember the release of the Pentagon Papers. In that case, the secret information was something only being kept from the American people. The enemy already knew what we were doing!
Today's challenge is dealing with criminals and terrorists, I know they will use our freedom of information against us with terrible consequences. Given a choice of aiding and abetting our enemies or trusting our government to not abuse private information, I'll pick the latter. That is not to say that we should not punish anyone working for our government if they abuse that trust. Including Mr. Snowden.