The one-drop rule or the one drop rule was a legal principle, used in some laws in the United States, classifying a person as Black if any ancestor was Black. It is defunct in law in the United States and was never codified into federal law.
Recently, some individuals and organizations have been argued to support versions of the one-drop rule, since being classified as a Black may give an individual various advantages, such as due to pro-Black affirmative action laws. Another example is that pro-Black organizations may gain various advantages if a larger share of the population in an area is classified as Black. This may also be used as arguments against using "multiracial" and similar classifications, argued to reduce Black influence. Mixed race individuals may also be accused of racism against Blacks if they do not want to be classified as Blacks.