The correct response is:
New York Times v. Sullivan determined that actual malice must be proven to pursue charges of libel in the case of a public official.
This landmark decision established that public officials must demonstrate that a statement is made with "actual malice" — meaning that it was made knowing it was false or with reckless disregard for the truth — in order to successfully sue for libel. This ruling significantly expanded freedom of speech by making it more difficult for public figures to silence criticism or dissent through libel lawsuits.