Is there any constitutional court in the US that can revoke unconstitutional laws? In my country (which has a totally different legal system, since court sentences cannot be directly used in future cases) any sentenced person can appeal to the constitutional court, and if the court finds that the sentence was based on an unconstitutional law, the invalid law gets revoked, and the sentenced person becomes a defendant again.
I'm just thinking whether Snowden's lawyers could use this kind of argument. Of course this is not that simple, since he disclosed a national secret, and I guess that national secrets regulations are perfectly constitutional.