US Supreme Court Justice Oliver Wendell Holmes Jr writing his dissenting opinion in November 1919 (Abrams v. United States):
Persecution for the expression of opinions seems to me perfectly logical. If you have no doubt of your premises or your power and want a certain result with all your heart you naturally express your wishes in law and sweep away all opposition….
But when men have realized that time has upset many fighting faiths, they may come to believe […] that the ultimate good desired is better reached by free trade in ideas—that the best test of truth is the power of the thought to get itself accepted in the competition of the market….
That at any rate is the theory of our Constitution. It is an experiment, as all life is an experiment…. While that experiment is part of our system I think that we should be eternally vigilant against attempts to check the expression of opinions that we loathe and believe to be fraught with death, unless they so imminently threaten immediate interference with the lawful and pressing purposes of the law that an immediate check is required to save the country.
Justice Holmes’s and the whole of the USA’s journey towards contemporary interpretation of the meaning of free speech in America is the subject of “Justice Holmes and the ‘Splendid Prisoner’” by Anthony Lewis, published in The New York Review of Books, Volume 56, Number 11 · July 2, 2009.