I find the responses to this thread particularly interesting and telling - especially from those who often proclaim the primacy of the Constitution and consistently decry the encroachment of the Federal Government into the rights of the individual, or indeed any increase in power of the Fed at all. ...but the minute it has to do with "national security", oh no, it's a whooooole different story. Then the LAW is your friend, and the individual is the bad guy. You're no different than Statist Democrats who want to repeal the 2nd Amendment. Same tune, different instrument.
The constitution makes it very clear what "Treason" is:
Treason against the United States, shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort. No Person shall be convicted of Treason unless on the Testimony of two Witnesses to the same overt Act, or on Confession in open Court.
The term "Enemies" is an important thing to take note of. "Enemies" exist during a time of war. If we are not at war, there can be no Treason. If you doubt this assertion have a look at the case-law surrounding it.
http://legal-dictionary.thefreedictionary.com/treason
If revealing the actions of our Government to the People of our Nation is Treason, then the inference is that the Government is at war with WE THE PEOPLE. If that's not a problem to you, then I don't know what is.
Revealing that we're spying on our friends and rivals in the world is not treason either - I'm quite certain their intelligence agencies and governments already know full well what we've been up to, since a great many people in this country already knew full well. Snowden didn't really reveal anything new - he just confirmed it. He's a whistleblower, and should have been protected by our laws protecting whistleblowers.
Regarding claims that he's a self-important douche: what he did IS important. I've seen nothing that makes it seem as though he regards himself as particularly important, but he clearly thinks that the American People have a right to know what's being done in their name and has placed his life in grave danger to tell them.