Here are his parents - take a good look at mom:
Records are a little thin, but the picture certainly speaks volumes. We was born into a VA family, part of which were black and another part of which was black - she lost her parents and had to move to live with white relatives in KS. Oral histories from VA identified her as being black. While somewhat light skinned, she definitely has features. AA folks can identify a "wave" in photos of her hair as she was elderly (I have no idea what that would mean). So the evidence is in the photos, plus the oral history. See pic below:
Coolidge is less clear - his mother died whe he was 12. He described her as "dark" from Indian ancestors. Her maiden name was "Moor", which was the last name commonly given to blacks in Europe and the "Indian" story was commonly used in New England as a polite way of describing blacks intermingled with whites. Again, circumstantial...
Upon deeper digging, Jackson falls apart (there was another Andrew Jackson, a few years younger who was partially black and wrote a book about it). Several historians confused and intermingled the two over the years. Likewise, the stories about Jefferson appear to not be factual. I stand corrected.
Warren Harding is another case of circumstantial evidence - although he never did deny it when asked straight up. He would just talk about "one in the woodpile" or "don't know if one jumped the fence". While he did attend a college founded for blacks, it did allow all races. Here is a photo of his cousin (the woman) - their fathers were brothers.
I'll call this one unclear - although his refusal to deny it during a time when that would've gained him favor (and he was a piss-poor President who could've used the boost).
He's a mess. His mother was a Melungeon, which gave him his dark complexion, eyes, color blindness, and hair - and potentially partially black, based on Melungeon makeup. non-Appalachians can look up Melungeons on their own. A lot of debate over who his father was, with the leading candidates all being white. He also had a long-term case of syphyllis and was alleged to be bi-sexual in addition to being either bi-polar or manic depressive.
My points are:
1) Race was less an issue in our past than it is today
2) Obie is more a sensation based upon his AA appearance rather than actual lineage.
3) History can be fun.