“It is said that this manifesto was more than a theory, that it was an incitement. Every idea is an incitement. It offers itself for belief and if believed it is acted on unless some other belief outweighs it or some failure of energy stifles the movement at its birth. The only difference between the expression of an opinion and an incitement in the narrower sense is the speaker’s enthusiasm for the result. Eloquence may set fire to reason. But whatever may be thought of the redundant discourse before us it had no chance of starting a present conflagration. If in the long run the beliefs expressed in proletarian dictatorship are destined to be accepted by the dominant forces of the community, the only meaning of free speech is that they should be given their chance and have their way.”
Oliver Wendell Holmes, Jr. writing for the dissent in Gitlow v. New York.