Most court opinions are made publicly available under the First Amendment so that people can understand what the law is and have trust in the judicial process. That is not the case for the Foreign Intelligence Surveillance Court (FISC) which decides when government agencies can spy on suspected foreign agents, and can sometimes target American citizens as well.
The Department of Justice sued Snowden in September for publishing his memoir without submitting it first for government review. Snowden's lawyers have argued that the government does not apply rules consistently and that much of the information in the book had already been made public.
“There is a strong likelihood that the government would have subjected Mr. Snowden specifically to such discriminatory treatment,” Snowden’s lawyers wrote. “A whistleblower the government considers to be a traitor would have been seeking permission from the very agencies on which he blew the whistle to speak about his views on surveillance."
According to the lawsuit, the DoJ is entitled to all monetary proceeds derived from the publication of his book because of contractual agreements Snowden signed while working as a government contractor.