"The question in every case is whether the words used are used in such circumstances and are of such a nature as to create a clear and present danger that they will bring about the substantive evils that Congress has a right to prevent. It is a question of proximity and degree. When a nation is at war many things that might be said in time of peace are such a hindrance to its effort that their utterance will not be endured so long as men fight and that no Court could regard them as protected by any constitutional right."

“Deep-seated preferences cannot be argued about — you cannot argue a man into liking a glass of beer — and therefore, when differences are sufficiently far reaching, we try to kill the other man rather than let him have his way. But that is perfectly consistent with admitting that, so far as appears, his grounds are just as good as ours.”

“Detached reflection cannot be demanded in the presence of an uplifted knife.”

“The power to tax is not the power to destroy while this Court sits.”

“When twenty years ago a vague terror went over the earth and the word socialism began to be heard, I thought and still think that fear was translated into doctrines that had no proper place in the Constitution or the common law. Judges are apt to be naif, simple-minded men, and they need something of Mephistopheles. We too need education in the obvious—to learn to transcend our own convictions and to leave room for much that we hold dear to be done away with short of revolution by the orderly change of law.”

“The general rule, at least, is that while property may be regulated to a certain extent, if regulation goes too far it will be recognized as a taking.”

“Holmes' Dissenting Opinion, Abrams vs. United States”