If he's the leaker, yes he is a traitor. But if he's not, but rather just disagrees with the policy, and will testify in closed session to the appropriate Congress Critters, and not to any Congressional staff. Then that's fine. But his is not the decision to release any information to anyone not cleared for it, except Congressmen of the appropriate positions. If he does that, he is guilty of a federal felony, and most likely guilty of treason.
He's a leaker but not the leaker in the current controversy because "he says he was not part of the intercept program which has been in the news."