“We shall demand complete toleration for the expression of any and every doctrine under the sun, even - and here is the acid test of our belief in toleration - of those doctrines which would forbid the expression of any except themselves. We must, in a word, be tolerant even of those views which deny tolerance. [...] Those who believe in freedom may not deny men the right to advocate unfreedom. We cannot in the name of a principle take action which denies the principle. Hence those of us who care for liberty must forgo the use of the weapon upon which its opponents pride themselves.”