Snowden is a very interesting case. On one hand, he seems to have an idealistic view of his actions. He sincerely believes that he did the right thing. On the other hand, he now has what most 29 yr olds would give anything for: international fame. The world is tracking his every move, people are starting to venerate him...I kind of trust that his motives were pure but this is one hell of a side benefit.
Does anyone remember when Kanye West looked into the camera and said "George Bush does not care about black people"? I think that he and Snowden are linked because they both felt very strongly about an issue, but couldn't or didn't pursue recourse through the proper channels. Anyone who saw Kanye's face before he made his statement could see the brew of fear and nervousness inside of him, because deep down he knew that his next action probably wasn't the right thing to do. I would guess that Snowden went through similar emotions. He absolutely had to do what he thought was right, but inside he knew that there was probably a better way.
Snowden isn't an agent of espionage or a traitor. He is a criminal, he clearly broke the law. The perceived Constitutionality of the NSA programs is irrelevant. The Constitution itself says clearly who is in charge of interpreting the Constitution. He doesn't get a pass based on his beliefs or because of our beliefs.
I hope he comes home and faces a trial. If he gets an OJ level superstar legal team he has a good chance of being found not guilty. If he loses he's facing around 10 yrs in a lower security prison. The show trial and national debate he'll spark will probably be more than worth it.