A defendent in any US court can move for summary dismissal on grounds that the alleged law that he broke is unconstitutional. According to the US Supreme Court, "An unconstitutional act is not a law; ... it is in legal contemplation as inoperative as though it had never been passed." Norton v. Shelby County, 118 U.S. 425 (1886). So the court doesn't really "revoke" laws, but rather declares that they were null and void ab initio (except in rare cases like VRA Section 4 (Shelby County v. Holder), which was held to become unconstitutional over the passage of time).
The US Supreme Court regularly decides on constitutionality, and its rulings are binding on all other courts in the country. But it is not a "constitutional court" in the sense of, e.g., Germany's Constitutional Court, because the US Supreme Court (1) only makes constitutional rulings when needed to resolve "actual cases or controversies", and (2) it also decides other matters not involving disputes over constitutional provisions.
> I guess that national secrets regulations are perfectly constitutional.
Yes, regardless of whether the NSA's spying is unconstitutional (and thereby illegal), it is clear that Snowden's actions were illegal under federal law.
The US Supreme Court regularly decides on constitutionality, and its rulings are binding on all other courts in the country. But it is not a "constitutional court" in the sense of, e.g., Germany's Constitutional Court, because the US Supreme Court (1) only makes constitutional rulings when needed to resolve "actual cases or controversies", and (2) it also decides other matters not involving disputes over constitutional provisions.
> I guess that national secrets regulations are perfectly constitutional.
Yes, regardless of whether the NSA's spying is unconstitutional (and thereby illegal), it is clear that Snowden's actions were illegal under federal law.