“Those who won our independence believed that the final end of the State was to make men free to develop their faculties, and that, in its government, the deliberative forces should prevail over the arbitrary. They valued liberty both as an end, and as a means.
They believed liberty to be the secret of happiness, and courage to be the secret of liberty. They believed that freedom to think as you will and to speak as you think are means indispensable to the discovery and spread of political truth; that, without free speech and assembly, discussion would be futile; that, with them, discussion affords ordinarily adequate protection against the dissemination of noxious doctrine; that the greatest menace to freedom is an inert people; that public discussion is a political duty, and that this should be a fundamental principle of the American government.
They recognized the risks to which all human institutions are subject. But they knew that order cannot be secured merely through fear of punishment for its infraction; that it is hazardous to discourage thought, hope and imagination; that fear breeds repression; that repression breeds hate; that hate menaces stable government; that the path of safety lies in the opportunity to discuss freely supposed grievances and proposed remedies, and that the fitting remedy for evil counsels is good ones.
Believing in the power of reason as applied through public discussion, they eschewed silence coerced by law — the argument of force in its worst form. Recognizing the occasional tyrannies of governing majorities, they amended the Constitution so that free speech and assembly should be guaranteed. Fear of serious injury cannot alone justify suppression of free speech and assembly. Men feared witches and burnt women.
It is the function of speech to free men from the bondage of irrational fears. To justify suppression of free speech, there must be reasonable ground to fear that serious evil will result if free speech is practiced. There must be reasonable ground to believe that the danger apprehended is imminent. There must be reasonable ground to believe that the evil to be prevented is a serious one.”
“Those who won our independence by revolution were not cowards. They did not fear political change. They did not exalt order at the cost of liberty. To courageous, self-reliant men, with confidence in the power of free and fearless reasoning applied through the processes of popular government, no danger flowing from speech can be deemed clear and present unless the incidence of the evil apprehended is so imminent that it may befall before there is opportunity for full discussion.
If there be time to expose through discussion the falsehood and fallacies, to avert the evil by the processes of education, the remedy to be applied is more speech, not enforced silence. Only an emergency can justify repression. Such must be the rule if authority is to be reconciled with freedom.”
Justice Louis D. Brandeis, Whitney v California https://www.law.cornell.edu/supremecourt/text/274/357