The Devil and the One Drop Rule: Racial Categories, African Americans, and the U.S. Census

For generations, the boundaries of the African-American race have been formed by a rule, informally known as the “one drop rule,” which, in its colloquial definition, provides that one drop of Black blood makes a person Black. In more formal, sociological circles, the rule is known as a form of “hypodescent” and its meaning remains basically the same: anyone with a known Black ancestor is considered Black. Over the generations, this rule has not only shaped countless lives, it has created the African-American race as we know it today, and it has defined not just the history of this race but a large part of the history of America.