Query: Prior to the 1900s, what was the socially accepted rule for racial interpretation?
Context: In their attempt to ensure white supremacy decades after emancipation, in the early 20th century, most southern states created laws based on the one-drop rule, defining as black, persons with any known African ancestry. This was a stricter interpretation than what had prevailed in the 19th century; it ignored the many mixed families in the state and went against commonly accepted social rules of judging a person by appearance and association. Some courts called it "the traceable amount rule."