New York Times Co. v. Sullivan (1964)
During the turbulent days of the early 1960s, a full-page ad appeared in the New York Times that claimed the arrest of Rev. Martin Luther King, Jr. for perjury in Montgomery, Ala., was part of a campaign to destroy King's efforts to integrate public facilities and encourage blacks to vote. In response, Montgomery city commissioner L.B. Sullivan filed a libel action against the newspaper and four black ministers listed as endorsers of the ad, claiming that the allegations against the Montgomery police defamed him personally. Under Alabama law, Sullivan didn't have to prove the harm to his reputation; the ad contained factual errors that precluded a truth defense. The challenge before the Court: Did Alabama's libel law infringe on the First Amendment's freedom of speech and press protection?
The Court held that the First Amendment protects the publication of all statements -- even those later proven false -- about the conduct of public officials unless they're made with actual malice, or knowledge that they're false or reckless. The Court dismissed Sullivan's case and established that publicly elected officials must prove an actual intent to harm in cases of libel or defamation.