“Yet to assimilate agitation, legitimate as such, with direct incitement to violent resistance, is to disregard the tolerance of all methods of political agitation which in normal times is a safeguard of free government.”

1920s, Ways to Peace (1926)
Context: Yet in time of stress and public agitation we have too great a tendency to disregard this policy and indulge in race hatred, religious intolerance, and disregard of equal rights. Such sentiments are bound to react upon those who harbor them. Instead of being a benefit they are a positive injury. We do not have to examine history very far before we see whole countries that have been blighted, whole civilizations that have been shattered by a spirit of intolerance. They are destructive of order and progress at home and a danger to peace and good will abroad. No better example exists of toleration than that which is exhibited by those who wore the blue toward those who wore the gray. Our condition today is not merely that of one people under one flag, but of a thoroughly united people who have seen bitterness and enmity which once threatened to sever them pass away, and a spirit of kindness and good will reign over them all.

What is to be Done? (1902)

John Maynard Keynes on hearing Gokhale speaking in Cambridge in [BR Nanda, Gokhale:The Indian Moderates and the British Raj, Princeton University Press]

Charles Evans Hughes, De Jonge v. Oregon, 299 U.S. 353, 365 (1937).
Judicial opinions
Context: Freedom of speech and of the press are fundamental rights which are safeguarded by the due process clause of the Fourteenth Amendment of the Federal Constitution. [... ] The right of peaceable assembly is a right cognate to those of free speech and free press, and is equally fundamental. As this Court said in United States v. Cruikshank, 92 U. S. 542, 552: The very idea of a government, republican in form, implies a right on the part of its citizens to meet peaceably for consultation in respect to public affairs and to petition for a redress of grievances. The First Amendment of the Federal Constitution expressly guarantees that right against abridgment by Congress. But explicit mention there does not argue exclusion elsewhere. For the right is one that cannot be denied without violating those fundamental principles of liberty and justice which lie at the base of all civil and political institutions — principles which the Fourteenth Amendment embodies in the general terms of its due process clause. [... ] These rights may be abused by using speech or press or assembly in order to incite to violence and crime. The people, through their legislatures may protect themselves against that abuse. But the legislative intervention, can find constitutional justification only by dealing with the abuse. The rights themselves must not be curtailed. The greater the importance of safeguarding the community from incitements to the overthrow of our institutions by force and violence, the more imperative is the need to preserve inviolate the constitutional rights of free speech, free press and free assembly in order to maintain the opportunity for free political discussion, to the end that government may be responsive to the will of the people and that changes, if desired, may be obtained by peaceful means. Therein lies the security of the Republic, the very foundation of constitutional government.

1850s, The Present Aspect of the Slavery Question (1859)
Context: This negative doctrine of Mr. Douglas that there are no rights anterior to governments is the end of free society. If the majority of a political community have a right to establish slavery if they think it for their interest, they have the same right to declare who shall be enslaved. The doctrine simply substitutes the despotic, irresponsible tyranny of many for that of one. If the majority shall choose that the interest of the State requires the slaughter of all infants born lame, of all persons more than seventy years of age, they have the right to slaughter them, according to what is called the Democratic doctrine. Do you think this a ludicrous and extreme case? But if the majority have a right to deprive a man of his liberty at their pleasure, they have an equal right to take his life. For life is no more a natural right than liberty. The individual citizen, according to Mr. Douglas, is not secure in his person, in his property, in his family, for a single moment from the whim or the passion or the deliberate will of the majority, if expressed as law. Might is not right. I have the power to hold a child by the throat until he turns purple and dies. But I have not the right to do it. A State or a Territory has the power to steal a man's liberty or labor, and to hold him and his children's children forever in slavery. It has the power to do this to any man of any color, of any age, of any country, who is not strong enough to protect himself. But it has no more right to do it to an African than to an American or an Irishman, no more right to do it to the most ignorant and forsaken foreigner than to the prosperous and honored citizen of its own country. We are going to do what Patrick Henry did in Virginia, what James Otis and Samuel Adams did in Massachusetts, what the Sons of Liberty did in New York, ninety years ago. We are going to agitate, agitate, agitate. You say you want to rest. Very well, so do we — and don't blame us if you stuff your pillow with thorns. You say you are tired of the eternal Negro. Very well, stop trying to turn a man into a thing because he happens to be black, and you'll stop our mouths at the same time. But while you keep at your work, be perfectly sure that we shall keep at ours. If you are up at five o'clock, we shall be up at four. We shall agitate, agitate, agitate, until the Supreme Court, obeying the popular will, proclaims that all men have original equal rights which government did not give and cannot justly take away.

Source: Quarterly Review, 116, 1864, pp. 265-266

http://www.marxists.org/archive/lenin/works/1903/2ndcong/5.htm
Second Congress of the RSDLP: Drafts of Minor Resolutions
July–August
1903
Collected Works
6
yes
Lenin
Vladimir Ilich
Marxists.
1900s

Letter to Marquis de la Fayette http://www.constitution.org/tj/jeff10.txt (November 4, 1823); in: The Writings of Thomas Jefferson, Memorial Edition (ME) (Lipscomb and Bergh, editors), 20 Vols., Washington, D.C., 1903-04, Volume 15, page 491
1820s

But since the Lecompton bill no Democrat, within my experience, has ever pretended that he could see the end. That cry has been dropped. They themselves do not pretend, now, that the agitation of this subject has come to an end yet.
1860s, Allow the humblest man an equal chance (1860)