We just did this topic in another thread:

The One Drop rule (or one-eighth African blood) was used in the South for segregation purposes under 'separate but equal.'
It gave constitutional legitimacy to Jim Crow segregation laws.
It was seen as a way to determine who is white and who is black. It was based on some scientific racism of the era.

Homer Plessy challenged the law. Plessy, by all appearances, was a white man. However, he had this one-eighth African Blood.

"Separate but equal" remained standard doctrine in U.S. law until it was over turned by the Supreme Court decision Brown v. Board of Education (1954).

In deciding Brown v. Board of Education, the Supreme Court rejected the ideas of scientific racists about the need for segregation.

So we no longer have that rule in America. It no longer applies. It has been overturned.

(P.S. I love history that is why I am always all up in these talks. Not to point fingers. Not everyone likes history. I just happen to have an interest)))