Chaplinsky v. New Hampshire
In Chaplinsky v. New Hampshire, 315 U.S. 568, 571-72 (1942), the U.S. Supreme Court held that "[t]here are certain well-defined and narrowly limited classes of speech, the prevention and punishment of which has never been thought to raise any Constitutional problem." Specifically, this decision declared "fighting words" to be outside the scope of the First Amendment when the words are likely immediately to incite a violent response.
This unanimous decision was written by Justice Murphy. Mr. Chaplinsky was a member of the Jehovah's Witnesses denomination, and he disputed, several key facts alleged against him, such as the claim that he used the name of God in his alleged "fighting words."