Donald Trump, you might want to learn something about L.B. Sullivan and the Supreme Court case he inspired.
Sullivan was a city commissioner in Montgomery, Alabama, in 1960 when The New York Times published a full-page advertisement criticizing "Southern violators" for infringing on the civil rights of student protesters and Martin Luther King Jr. Sullivan brought a libel suit, claiming he had been defamed, and in the lower courts he won.
Alabama law permitted public officials to recover damages for false statements -- and some of the facts in the ad were incorrect -- that "tend to injure a person ... in his reputation" or "bring [him] into public contempt."
The Supreme Court reversed. "We consider this case," Justice William Brennan wrote in 1964, "against the background of a profound national commitment to the principle that debate on public issues should be uninhibited, robust, and wide-open, and that it may well include vehement, caustic, and sometimes unpleasantly sharp attacks on government and public officials."