What is the test for intervention in the case of freedom of speech in the United States?

Consider first the proposition that some rights are more important than others (and the corollary - based upon the changing ideas about freedom and democracy already stressed - that the importance of rights changes in time and circumstance). Holmes, J. formulated the “clear and present danger” test as the U.S. standard for intervention in the case of freedom of speech. See: Schinck v. U.S. 249 U.S. 47 (1919) and Abrams v. U.S. 250 U.S. 616 (1919). The argument was and remains that freedom of speech is so important that no significant interruption of it should be thought necessary unless the very existence of the state is at risk. It is not enough even that there be a compelling state interest for a limitation.