As a worldwide historical institution slavery was not race or color coded. Slavery existed in all societies for as long as there has been recorded history. It was the institution that lifted Europe from a medieval backwater to universal hegemony – for a time. In the West slavery as an institution fell out of favor because of the ideals of the Enlightenment and the development of a Christian theology that rejected slavery as sin.
The institution of slavery in the United States was unique in a number of ways. One very important difference between slavery in the United States (or British North America) and elsewhere was that it was the only self-propagating slave population in history. Whereas in the rest of the Americas a slave owner could only count on useful labor from a slave for about six years, at which point the slave was manumitted (put out to die) and replaced, in the United States slaves were bred like animals. In many cases the breeding was accomplished by slave owners, which is why the law called for slavery to be hereditary through the mother.
The United States is also unique in that race became legally color coded. In a deliberate effort to drive a wedge between poor free blacks and whites (to prevent racial solidarity in the face of wealth inequality, look up Bacon’s Rebellion) laws were enacted that restricted, and eventually eliminated, the rights of blacks while making token accommodations for poor whites. The whites were materially little better off than the blacks, but the white man could always look down on the black man: “at least I’m not black.” In many parts of the United States it became illegal for a black person to be free. To say that slavery in the United States was not racist is absurd and demonstrates a dangerous ignorance of essential historical knowledge.
The disconnect between race and slavery occurred where a sentiment developed that slavery was wrong and should be ended (abolitionism) while at the same time believing that black people were not capable of assimilation to white culture, certainly not to equal political status. This is where we see the “send them back to Africa” idea arise. Many early abolitionists subscribed to the idea and the American Colonization Society was formed to expatriate former slaves to Liberia. Abraham Lincoln at one point supported this idea.
Of course, the problem with the “send them back to Africa” idea was that they weren’t from Africa. The slave trade had ended legally in the United States in 1808, so theoretically every slave in the United States had been born there. There was still smuggling, so the prohibition was not absolute, but the impact of smuggled slaves on the slave population was small compared to natural reproduction.
The language of the Fourteenth Amendment (“All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and the State wherein they reside.”) was radical in that the idea of granting citizenship rights to former slaves was controversial. It wasn’t just controversial in the South, it was so in the United States, which demonstrates that while many people were in favor of abolition, they were at the same time racist in their belief that black people are inferior. That idea persisted. When the Armed Services were integrated by Pres. Truman it wasn’t the Southern armed services, it was the American. When Jackie Robinson first played in the major leagues in 1947 it wasn’t Southern baseball that was integrated, it was American. Americans often attempt to localize the sin of racism in the South and thereby absolve themselves, but racism is so embedded in the American consciousness that when you protest racism people think you are protesting America.
Slavery in the United States was racist, and racism didn’t end with the abolition of slavery.