He argued several times against slavery. As a young lawyer he also defended a slave who sued for freedom pro bono and made an eloquent speech. He went beyond legal technicalities, and argued from his natural rights perspective saying: "We assert that under the law of nature all men are born free, and every one comes into this world with a right to his own person."
Again, in 1774, in a pamphlet entitled A Summary View of the Rights of British America, Jefferson-- in a section that listed grievances against King George III's mistreatment of the colonists-- wrote these astonishing words:
"[H]is Majesty has rejected laws of the most salutary tendency. The abolition of domestic slavery is the great object of desire in these colonies where it was unhappily introduced in their infant state. But prervious to the infranchisement of the slaves we already have, it is ncessary to exclude all further importations from Africa. Yet our repeated attempts to effect this by prohibition and by imposing duties which might amount to a prohibition, have been hitherto defeated by his majesty's negative: thus preferring the immediate advantages of a few British corsairs to the lasting interests of the American states *and to the rights of human nature* deeply wounded by this infamous practice." (The Portable Thomas Jefferson: pp. 14-15)
It is worth noting that this indignant passage is predicated on the fiction that American colonists in Virginia were prepared to end slavery. Nobody took issue with Jefferson for making the claim, but it is clear in retrospect that Jefferson was a) leveling not a legal but distinctly MORAL charge against the King, and that b) in doing so he falsely spoke for the population of Virginia. Perhaps because it was inconsequential (nobody was about to act on it), nobody took Jefferson to task for being presumptive. But equally conspicuous is the high and abstract, universal idealism to which Jefferson gives expression. He did so again when writing his unedited draft of the Declaration of Independence where the original list of grievances includes this:
"[The King has] waged cruel war against human nature itself, violating the sacred rights of life and liberty in the persons of a distant people who never offended him, captivating and carrying them into slavery in another hemisphere, or to incur miserable death in their transportation hither....Determined to keep open a market where MEN [sic] should be bought and sold, he has prostituted his negative for suppressing every legislative attempt to prohibit or to restrain this execrable commerce." (ibid)
Again, Jefferson (knowingly or not) is playing fast and loose with the facts by suggesting that the King foisted the institution of slavery on an unwilling and morally resistant group of colonists. Jefferson's relationship to the truth was sometimes strangely deficient. Some historians note that he wrote these and other passages with a kind of philosophical passion and moral urgency that seems to have been sincere. But at the next moment he would command his slaves, or sell them to pay debts off. Worst of all, of course, was his long affair with Sally Hemmings.
So while he was our most compelling and eloquent spokesperson for natural rights, he also recorded feelings of fear and guilt.
"I tremble for my country when I reflect that God is just; that his justice cannot sleep forever....The Almighty has no attribute which can take sides with us." (Ellis: p.25)
Yet he also wrote:
Nothing is more firmly written in the book of fate than that these people [African Americans] are to be free; nor is it less certain that the two races -- equally free-- cannot live in the same government. Nature, habit, opinion has drawn *indelible* distinctions between them" (ibid)
He went on to explain that if slaves were to be freed without being expatriated, the effects on whites would be heaviest of all, since by virtue of having "negro blood" they would "contaminate" whites and generate "an inferior American race" (p. 26 Ellis) He concludes:
"When freed they must be removed beyond the reach of mixture."
Various scholars wrote Jefferson agreeing that slaves should be freed, but parting ways with him on what they saw-- even then -- as crackpot race science. David Ramsay wrote:
"I think you have depresssed the negroes too low. I believe all mankind to be originally the same and diversified by accidental circumstances." (Ellis: 26)
Jefferson's friend, Dr. Benjamin Rush, wrote:
"The unhappy sons of Africa, in spite of the degrading influence of slavery, are in no wise inferior to the more fortunate inhabitants of Europe and America."
But Jefferson was adamant about the inherent inferiority of any person with"African blood." Any racial "mixture" would, he thought, result in biological degradation of whites, or as he put it, "mongrelization."
So, this appears to be an example of our most moralistic egalitarian defender of all human rights including those of African slaves. Yet he was one of the more severe racists. How does that work? How can one compartmentalize to that degree?
Similarly, Enlightenment philosophers who espoused universal rights including Kant, Hume and later figures like Hegel held that Africans were a separate and inferior race. Such beliefs were common. But they didn't father "mulattoes" as far as I know. Even prototypical civil rights architect, socialist and feminist, John Stuart Mill couldn't bring himself to believe that Britain's Indian subjects were capable of ruling themselves. All his work on liberty in politics simply didn't apply!
[S]elf-government ensued, which resulted, on the 4th of July, 1776, in a Declaration, by the Colonies, "that they are, and of right ought to be, FREE AND INDEPENDENT STATES; and that, as free and independent States, they have full power to levy war, conclude peace, contract alliances, establish commerce, and to do all other acts and things which independent States may of right do."(sic) https://avalon.law.yale.edu/19th_century/csa_scarsec.asp
Abolitionist, William Lloyd Garrison, wrote The Declaration of Sentiments of the American Anti-Slavery Convention in 1833. He cites the "immortal declaration" while insisting that to make the principle of equality true in practice, all slaves in the US must be freed immediately.
"More than fifty-seven years have elapsed, since a band of patriots
convened in this place, to devise measures for the deliverance of this
country from a foreign yoke. The corner-stone upon which they founded
the Temple of Freedom was broadly this—'that all men are created
equal; that they are endowed by their Creator with certain inalienable
rights; that among these are life, LIBERTY,
and the pursuit of happiness.' At the sound of their trumpet-call,
three millions of people rose up as from the sleep of death, and
rushed to the strife of blood; deeming it more glorious to die
instantly as freemen, than desirable to live one hour as slaves. They
were few in number—poor in resources; but the honest conviction that
Truth, Justice and Right were on their side, made them invincible.
We have met together for the achievement of an enterprise, without
which that of our fathers is incomplete.... Their grievances, great as they were, were trifling in comparison
with the wrongs and sufferings of those for whom we plead. Our fathers
were never slaves—never bought and sold like cattle —never shut out
from the light of knowledge and religion—never subjected to the lash
of brutal taskmaster." (Selections from the Writings of W.L Garrison: pp. 67-8: http://utc.iath.virginia.edu/abolitn/abeswlgct.html )
Frederick Douglass also invoked the principle in stirring words, while holding it up to Americans as an unrealized ideal-- indeed a measure of hypocrisy and moral failure. In his famous speech on Independence Day of 1852, "What to the Slave Is the Fourth of July?" Douglas said:
"The signers of the Declaration of Independence were brave men. They were great men too-- great enough to give fame to a great age. It does not often happen to a nation to raise, at one time, such a number of truly great men. The point from which I am compelled to view them [i.e. as a slave] is not, certainly, the most favorable; and yet I cannot contemplate their great deeds with less than admiration. They were statesmen, patriots and heroes, and for the good they did, and the principles they contended for, I will unite with you to honor their memory....Their statesmanship looked beyond the passing moment, and stretched away in strength into the distant future. They seized upon eternal principles, and set a glorious example in their defense. Mark them!"
He then indicts the nation for its failure to apply their principles to the millions of slaves in whose name he is speaking:
"Fellow citizens, pardon me, allow me to ask, why am I called upon to speak here today? Are the great principles of political freedom and of natural justice, embodied in that Declaration of Independence extended to us?....[S]uch is not the state of the case...I am not included within the pale of this glorious anniversary! Your high independence only reveals the immeasurable distance between us...The sunlight that brought life and healing to you, has brought stripes and death to me. This Fourth of July is yours, not mine. You may rejoice; I must mourn. To drag a man in fetters into the grand illuminated temple of liberty, and call upon him to join you in joyous anthems, were inhuman mockery and sacrilegious irony. Do you mean, citizens, to mock me by asking me to speak today?....The existence of slavery in this country brands your republicanism as a sham, your humanity as a base pretence, and your Christianity as a lie. It saps the foundation of religion; it makes your name a hissing, and a bye-word to a mocking earth. It is the antagonistic force in your government, the only thing that seriously disturbs and endangers you Union."
He then answers disdainfully the titular question of the speech:
"What, to the American slave, is your 4th of July? I answer; a day that reveals to him, more than all other days in the year, the gross injustice and cruelty to which he is the constant victim. To him, your celebration is a sham; your boasted liberty, an unholy license; your national greatness, swelling vanity; your sounds of rejoicing are empty and heartless; your denunciations of tyrants, brass-fronted impudence; your shouts of liberty and equality, hollow mockery... a thin veil to cover up crimes which would disgrace a nation of savages!" (Frederick Douglass: Selected Speeches and Writings, ed. Philip S Foner, available online here: https://liberalarts.utexas.edu/coretexts/_files/resources/texts/c/1852%20Douglass%20July%204.pdf )
I quote from this speech extensively in order to point to the nature of the American paradox of liberty and slavery. Douglass affirms the greatness of of the signers of the Declaration, and the "eternal principles" which they "seized" setting a "glorious example" for all posterity. Simultaneously, he reviles the nation 75 years later, for violating the true meaning of the very Declaration he has been asked to praise in speech. This, I think, has long been the pattern of those who effectively protest for human and civil rights. They don't say, "your tradition and morality is rotten" but rather "your understanding and practice of your own tradition and morality is rotten, and can only be rectified by recognizing my humanity and civil rights." America's ideal culture is the most valuable resource for those who would improve its real one.
Contrast that with those slavers and southerners who ultimately seceded from the union. In order to justify their secession they went out of their way to ridicule the "immortal declaration." John Randolph said that the idea that all are "created equal" was a "pernicious falsehood," citing obvious inequalities like the different mental and physical abilities of children and adults. John Calhoun (in)famously said that "there was not a word of truth" in the idea that all men are created equal." He held that the "natural state of Man" and the state into which "he is born, lives and dies" is one of "subjection to authority," and therefore a state of inequality.
It fell to Lincoln, the "Great Emancipator," to convert Jeffersonian egalitarianism, and the "immortal declaration" into a moral and political tool that would justify not just emancipation, but the Civil Rights Amendments (13th,14th and 15th) which, though he didn't live to see them, redeemed it legally thus changing the US Constitution. While Southerners scorned the idea of equality and universal rights, and Stephen Douglas argued that the Declaration was meant only for whites, Lincoln referred to Jeffersonian principles and quotations regularly, and insisted that they be taken at face value. He said:
"They [the founders] did not mean to say all were equal in color, size, intellect, moral developments, or social capacity...They defined...in what respects they did consider all men created equal... Men are equal in having certain inalienable rights, among which are life liberty and the pursuit of happiness. This they said, and this [they] meant. (Maier: p. 885)
Lincoln claimed in an 1861 Address, that he "never had a feeling politically that did not spring from the sentiments embodied in the Declaration of Independence." He stated that the assertion that "All Men Are Created Equal" was "the great fundamental principle upon which our free institutions rest." It was, he said, "the father of all moral principle."(ibid) During the War, Lincoln invited Frederick Douglass to the White House on 3 occasions (the first time an African American entered that building not as a worker or slave, but as a sought after advisor and guest). By the third and last meeting, Douglass had come to appreciate the importance of the egalitarian tradition as appropriated by Lincoln and the Radical Republicans (see Wilentz: 2016) For under Lincoln these moral and political principles bore fruit for enslaved Americans rather than mocking them. Freed blacks after the Emancipation Proclamation were eager to become part of America, to enjoy liberty and pursue happiness. The Civil War amendments had woven these ideals into the fabric of the US Constitution; and for a time, during Reconstruction, some 2,000 black Americans held public office,
from the local level all the way up to the U.S. Senate. They set up black colleges, small businesses, and tried to obtain promised land on which to put down viable roots. Tragically, all of this was met with the furious backlash that was Jim Crow and Lynch Law, and so justice was deferred until the Civil Rights era of the 1950s and 60s. And much remains to be done now.
Frederick Douglass wrote in his 1865 eulogy for Lincoln that he “was emphatically the black man’s President: the first to show any respect to their rights as men.” In a later speech toward the end of reconstruction, he honored Lincoln as the great emancipator, but added that he was ultimately the white man's president. Referring to Lincoln's Jeffersonian egalitarianism and its limits for blacks, he explained
“While Abraham Lincoln saved for you [i.e. whites] a
country, he delivered us from a bondage, according to Jefferson, one
hour of which was worse than ages of the oppression your fathers rose in
rebellion to oppose." (fr. Speech at Freedman's Monument, 1876 https://edan.si.edu/transcription/pdf_files/12955.pdf
So while understanding that Lincoln's first priority was to save the country, and only secondarily to "deliver [slaves] from bondage," he came to see this not as a flaw or failing on Lincoln's part, but a recognition of his responsibility to the preservation of the Union as a president, and his partial understanding of the plight of blacks in America given his circumstances and background. He continued:
"When, therefore, it shall be asked what we [African Americans] have to do with the memory of Abraham Lincoln, the answer is ready, full, and complete. Though he loved Caesar less than Rome, though the Union was more to him than our freedom or our future, under his wise and beneficent rule we saw ourselves gradually lifted from the depths of slavery to the heights of liberty and manhood; under his wise and beneficent rule, and by measures approved and vigorously pressed by him, we saw that the handwriting of ages, in the form of prejudice and proscription, was rapidly fading away from the face of our whole country; under his rule, and in due time, about as soon, after all, as the country could tolerate the strange spectacle, we saw our brave sons and brothers laying off the rags of bondage, and being clothed all over in the blue uniforms of the soldiers of the United States...[W]e saw the internal slave trade which so long disgraced the nation, abolished, and slavery abolished in the District of Columbia; under his rule we saw...the first slave-trader hanged like any other pirate or murderer...we saw the Confederate States, based upon the idea that our race must be slaves, and slaves forever, battered to pieces and scattered to the four winds; under his rule, and in the fullness of time, we saw Abraham Lincoln, after giving the slaveholders three months' grace in which to save their hateful slave system, penning the immortal paper...making slavery forever impossible in the United States. Though we waited long, we saw all this and more." (ibid)