Eugene Volokh:

I don’t think that’s consistent with the First Amendment, even if limited to knowingly false statements of fact. The Supreme Court has held that “prosecutions for libel on government have [no] place in the American system of jurisprudence,” regardless of whether the government thinks it can show that the statements are knowingly false: Even outright lies that damage the government’s reputation are thus constitutionally protected. Likewise, the 3-Justice dissent in U.S. v. Alvarez concluded that,