The "shouting fire in a crowded theater" mantra came from an offhand analogy by justice Oliver Wendell Holmes in a 1919 Supreme Court decision, Schenck v. United States. That decision was overturned in 1969, Brandenburg v. Ohio.

The Schenck decision also gave us the nebulous "clear and present danger" limit by the government on free speech/press/assembly which was replaced by the Brandenburg decision with "imminent lawless action." With the Brandenburg test, the government has to prove three elements: intent, imminence and likelihood.