The rule of law in claims of defamation or libel states that the First Amendment requires "actual malice," meaning that it requires that the plaintiff show that the defendant knew the statements were false or acted with gross recklessness, with intent, when publishing something.
Case Study of: New York Times Co. v. United States, 403 U.S. 713 (1971)
The rule of law is that "The First Amendment overrides the federal government's interest in keeping certain documents, such as the Pentagon Papers, classified."