“…the white man is being systematically indoctrinated into believing that he is guilty of enslaving and abusing the Negro. Granted that some Negroes were mistreated as slaves, the fact still remains that nowhere in all history or in the world today has the Negro been better off. The life expectancy of the Negro increased when he was transported to America. He was not taken from freedom into slavery, but from a vicious slavery to degenerate chiefs to a generally benevolent slavery in the United States. There is not the slightest evidence that any American Negro had ever lived in a "free society" in Africa; even the idea did not exist in Africa. The move from Africa to America was a vast increase of freedom for the Negro, materially and spiritually as well as personally. The Negroes were sold from a harsh slavery into a milder one. Slavery was basic to the African way of life, to the point that slaves were the actual money of the African economy. Elsewhere, gold and silver served as money; in Africa, it was slaves…”

Regents of University of California v. Bakke, 438 U.S. 265, 400-401 (1978) (Marshall, J., concurring in part and dissenting in part).

Fourth Lincoln-Douglass Debate http://www.nps.gov/liho/learn/historyculture/debate4.htm (September 1858)
1850s

1860s, Allow the humblest man an equal chance (1860)
Context: These natural and apparently adequate means all failing, what will convince them? This, and this only; cease to call slavery wrong, and join them in calling it right. And this must be done thoroughly — done in acts as well as in words. Silence will not be tolerated — we must place ourselves avowedly with them. Douglas's new sedition law must be enacted and enforced, suppressing all declarations that Slavery is wrong, whether made in politics, in presses, in pulpits, or in private. We must arrest and return their fugitive slaves with greedy pleasure. We must pull down our Free State Constitutions. The whole atmosphere must be disinfected of all taint of opposition to Slavery, before they will cease to believe that all their troubles proceed from us. So long as we call Slavery wrong, whenever a slave runs away they will overlook the obvious fact that he ran because he was oppressed, and declare he was stolen off. Whenever a master cuts his slaves with the lash, and they cry out under it, he will overlook the obvious fact that the negroes cry out because they are hurt, and insist that they were put up to it by some rascally abolitionist.

1860s, Allow the humblest man an equal chance (1860)

Source: Writings, Politics of Guilt and Pity (1978), p. 19

Speech http://teachingamericanhistory.org/library/document/the-nations-problem/

Speech in Indianapolis, Indiana (26 February 1863).
Quote

1860s, Allow the humblest man an equal chance (1860)
Context: So that saying, "in the struggle between the negro and the crocodile," &c., is made up from the idea that down where the crocodile inhabits a white man can't labor; it must be nothing else but crocodile or negro; if the negro does not the crocodile must possess the earth; [Laughter; ] in that case he declares for the negro. The meaning of the whole is just this: As a white man is to a negro so is a negro to a crocodile; and as the negro may rightfully treat the crocodile, so may the white man rightfully treat the negro. This very dear phrase coined by its author, and so dear that he deliberately repeats it in many speeches, has a tendency to still further brutalize the negro, and to bring public opinion to the point of utter indifference whether men so brutalized are enslaved or not.

Source: 2000s, A New Birth of Freedom: Abraham Lincoln and the Coming of the Civil War (2000), p. 526