>The phrase is a paraphrasing of a dictum, or non-binding statement, from Justice Oliver Wendell Holmes Jr.'s opinion in the United States Supreme Court case Schenck v. United States in 1919, which held that the defendant's speech in opposition to the draft during World War I was not protected free speech under the First Amendment of the United States Constitution.

This phrase was coined when the government, having arrested somebody for handing out leaflets opposing the draft in WW1, claimed that handing out leaflets opposing the draft was the moral equivalent of shouting fire in a crowded theater.