I hope this answer is not too specific for centering around American history, or too vague because it does span a few centuries.

Slavery was a common byproduct of conquest in Europe, Asia, and the Americas well before the Atlantic Slave Trade (listed here), but took on the form of commercial enterprise when the Americas were being colonized, and a permanent exploitable underclass became something that profitable trade demands.

Native Americans were enslaved by the Spanish since 1492, and forced into labor, but they were also uncooperative, they still had lives to return to and were able to mount a resistance. The Portuguese began taking African slaves around this time, and the first slaves in Virginia came shortly after the first permanent settlement in 1619. But there was also a large influx of white Europeans, who were not entirely slaves, but indentured servants.

Though in colonial America & especially the tobacco culture of the South, African slavery shared a lot of similarities with white servitude. Both were legal means of human trafficking, with a profitable trade of the servants themselves, and the products of their forced labor.

While there were many involuntary white servants, and those misled by illusions of opportunity and grandeur, there were also many poor volunteers. African slaves were all involuntary. They were separated from their families and cultures, many of them on slave ships were fearful of being eaten and committed anomic suicides. As a white servant, you faced similar conditions and a similar 10-20% mortality rate during the voyage. You were still crowded under the deck, crying, festering in disease, and pooping in the bucket, but those servants still had social ties, a common language, and some hope for the future. African slaves were totally uprooted from language and culture, and those that brought along family members could hope to stay together, as long as they didn't die and have their corpses cast into the sea.

Indentured servants lived in a grey area with certain rights being denied, and other freedoms being afforded to them that African slaves didn't have. They could be rented out and inherited, whipped and punished (within reason), and they could not trade or vote, but they could own property. They were also able to sue, although the courts were not likely to prevent abuse. Slaves, to a greater degree than white servants, were kept at a bare subsistence to maximize profit, while servants were at least promised land and basic tools after they filled their terms & were provided with alcohol.

After working for a number of years under their contract, (and however long it had been extended based on runaways and dead family members), most of them could expect to live freely as small, low-income farmers. Very few of them became prominent figures, Benjamin Franklin being a notable exception. Franklin was a servant in his brother's print shop from age 12 until he was 21. He was only paid for his last year of labor.

During the 1600s, the American colonies were not nearly as diverse. In the 1700s, you see a wide variety of immigrants, especially Germans, the Scotch-Irish, and the largest stream of immigration, African slaves. Slavery grew to replace white indentured servitude during the 1600s. Bacon's Rebellion in 1676 is recognized as a turning point in the decision-making of the Virginia ruling class, which was fearful of indentured servants conspiring with slaves, and the lower classes of poor whites conspiring with free blacks.

By the time of the Revolution, half the population of the Middle & Southern colonies were not English. Benjamin Franklin expressed the fear that "they will soon outnumber us, that all the advantages we have, will in my opinion, be not able to preserve our language, and even our government will become precarious." The American colonies were part of the British Empire, and white settlers thought of itself as English, but they were willing to accommodate Europeans while excluding Native Americans and African slaves from their newly-conceived American identity.

In the 1700s, you begin to see more laws forbidding slave gatherings, forbidding them to trade and drink liquor, and of course slavery becomes the backbone of the Southern economy, the basis of wealth for large plantation owners, and a source of raw materials for merchants and manufacturers in the North. With the passing of slave codes, slavery is increasingly identified with race.

Around the time of the Revolution, indentured servitude was being replaced by slavery in the South and wage labor in the North. And while Northern colonies began to eliminate slavery, and the slave trade was eventually forbidden, they also passed strict laws against free blacks. In my state of Ohio, they passed a law in 1804 which required blacks & mulattoes to obtain a "certificate of freedom" or leave the state. In 1807 they were not allowed to enter the state without posting a bond of $500 guaranteeing their good behavior. This was more heavily enforced in the 1820's, and in 1829, Cincinnati told black residents they have 60 days to post bond or get out of town. Before the time was up, white mods attacked a black district, killing & burning homes. Afterwards, 1,000 free blacks fled to Canada and established the Wilberforce Colony in Ontario. Other race riots and anti-abolition riots occurred throughout the North during the 1800's.

After the Revolution, American politics was governed by the Virginia Dynasty. Jefferson's agrarian vision of America with an emphasis on virtuous farmers was adopted by Southern plantation owners, and Monroe's ideals of American exceptionalism emphasized a homogeneous population that strives towards unity. 14 presidents owned slaves, and few early Presidents deserve credit for their antislavery leanings when forced labor and racial subjugation were the basis of their wealth and status and most of their slaves stayed in bondage. Even the non-slaveholder President John Adams was still fearful of blacks staging a rebellion, only Quincy Adams and Lincoln are notable exceptions. The Haitian Revolution and different slave rebellions still horrified the ruling class, while Jefferson, Madison, and Monroe were all members of the American Colonization Society, the effort to remove free blacks from the country by sending them to colonies in Liberia. By this point, slavery was well associated with race. Antislavery efforts and even abolitionists often excluded notions of racial equality.

Southern intellectuals in the 1800s would try to defend slavery, and assert the inferiority of black people to superior and apparently civilized white Europeans. John Calhoun argued that black slavery was not a necessary evil, but rather a "positive good," and superior to Northern wage slavery, but he shies away from the natural conclusion of that line of thinking, that there would be no reason to exempt white Americans from slavery. A few pro-slavery radicals like George Fitzhugh did actually hold this view. Abraham Lincoln, who hated Fitzhugh, still made statements against racial equality and did not move to end slavery until 1863 and with the 13th Amendment. Racial equality was firmly denied for another century.

My main source here is Richard Hofstadter's America at 1750, especially regarding white servitude. I would also look at Winthrop Jordan's "White Over Black: American Attitudes Toward the Negro, 1550-1812."