The Department of Justice has filed a lawsuit against Edward Snowden alleging that his newly released memoir, Permanent Record, violates nondisclosure agreements he signed with the federal government. Justice Department lawyers say the U.S. is entitled to all of Snowden's book profits.
I'm fairly sure unConstitutional contracts are unenforceable.
That doesn't matter though. He chose to sign the agreements then he knowing broke the agreements. The issue is about NDAs and someone knowingly breaking his 2 NDAs multiple times. This is illegal and he is being held accountable for it.
I dont see how his NDAs forced him to break the law? It requires him to disclose what information he wants to tell the public to the information owners (NSA, CIA) as any information he has about them belong to them and not to him. This is normal of most if not all NDAs.
He chose to not follow approved guidelines about reporting misconduct and misuse. He chose to take classified information to the Chinese government and then to the Russian government. He chose to break the legal contracts that he knowingly and in good faith signed.