Shouting fire in a crowded theater - Wikipedia, the free encyclopedia
The Schenck case
Holmes, writing for a unanimous Court, ruled that it was a violation of the Espionage Act of 1917 (amended with the Sedition Act of 1918), to distribute flyers opposing the draft during World War I. Holmes argued this abridgment of free speech was permissible because it presented a "clear and present danger" to the government's recruitment efforts for the war. Holmes wrote:
The most stringent protection of free speech would not protect a man falsely shouting fire in a theater and causing a panic. [...] The question in every case is whether the words used are used in such circumstances and are of such a nature as to create a clear and present danger that they will bring about the substantive evils that Congress has a right to prevent.