system
A chat on subreddit /r/NoStupidQuestions
human
were mulattos not seen as being black? under the law they would be right?
gpt
Generally yes, quantitative racial classifications usually work under one-drop rules, so mulattos were “colored people” but not necessarily the same as being “negroes”. There are substantial social implications to being mixed-race in the context of slavery in the US. Many (most?) biracial people at that time will have been fathered by well-off white men who owned and raped their enslaved women. Their offspring are more likely to be decently educated and more likely to be free. Jefferson fathered several children with one of his slaves, made sure they would be able to make a living for themselves, and manumitted them as they grew up, for example. It is likely the older presidents would expect Obama to be the bastard son of a rich white man who managed to rise up under his father’s guidance. At the time many people both pro- and anti-slavery held the paternalistic belief that black people were inherently inferior and required the “guidance” of white people. The notion that a biracial person could have been successfully *elevated* to that high level through the genetic and social influence of their presumed-white father is still entirely compatible with this belief system. 

Of course, they’d be in for a bit of an awakening when they found out that his mother was the white one, but at first meeting they would likely be less surprised and horrified than most commenters are expecting. The fact that the US holds the Hawaiian islands, freshly “discovered” at the time of the revolution and an independent kingdom for most of the 19th century, would likely be more interesting.