Racial segregation in the United States was based on a binary classification, white vs. non-white, in which "white" was held to imply "purity" so that anyone with even the slightest amount of non-white ancestry was excluded from white privileges, and there could be no category of racially mixed people. In 1896 this doctrine was upheld in the "Plessy v. Ferguson" Supreme Court case. Traditionally the main distinction was between "white" and "black", but Japanese Americans could be accepted on both sides of the divide. As further racial groups were categorized, "white" became narrowly construed, and everyone else was categorised as a "person of color", suggesting that "white" people have no race, while racial subdivision of those "of color" was unimportant.