"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 Congress shall have Power to declare the Punishment of Treason, but no Attainder of Treason shall work Corruption of Blood, or Forfeiture except during the Life of the Person attainted."
I have no doubt the answer will be offered based on political leaning so give a rational reason for your vote.
No he isn't committing treason.
1) He hasn't levied war against the United States.
2) He hasnt given Aid and Comfort to our enemies.
3) There are no witnesses any act.
His confession to whistleblowing the NSA scandal, in and of itself, cannot be enough to convict him. They still need witnesses. Corpus delicti Rule.
And you can't have witnesses to something he hasn't done. Since he hasnt levied war or given aid and comfort to our enemies, he cannot be convicted of treason.