Unique among nations, the United States has, during most of its history, categorized its inhabitants simplistically as Black or white, sometimes with a category for mulattos, now called “biracial.” Scientifically, however, human “races” do not exist. This U.S. practice known as the “one drop rule” was law in southern states that formally legislated the percentage of African ancestry, or “black blood,”  that mandated that a person be officially classified as Black, irrespective of phenotype which, after so much dilution, might be white. Afro-Brazilians, in contrast, may identify as Black or brown, “negro o pardo” based on phenotype, whereas in the United States, “brown” equals Black. Although it is now less official law than customary behavior in the U.S., many people who would identify differently elsewhere in the Americas, would be Black in the United States. A result has been that U.S. African Americans have had a solid collective identity foundation from which to fight institutional racism, in contrast to the situation in alleged “racial democracies” where structural racism has been more difficult for its victims to identify and combat.