"One Drop" Was Law in Virginia for Much of the Twentieth Century: Virginia's Racial Identity Act 1924-1975
"On March 20, 1924, the Virginia General Assembly passed....SB 219, titled 'The Racial Integrity Act'....The Racial Integrity Act required that a racial description of every person be recorded at birth and divided society into only two classifications: white and colored (essentially all other, which included numerous American Indians). It defined race by the 'one drop rule', defining as 'colored' persons with any African or Native American ancestry. It also expanded the scope of Virginia's ban on interracial marriage (anti-miscegenation law) by criminalizing all marriages between white persons and non-white persons."
"In 1967 the US Supreme Court ruled in Loving v. Virginia that the portion of the Racial Integrity Act that criminalized marriages between 'whites' and 'nonwhites' was found to be contrary to the guarantees of equal protection of citizens under the Fourteenth Amendment to the United States Constitution. In 1975, Virginia's Assembly repealed the remainder of the Racial Integrity Act."
The one-drop policy was waived for some distant descendants of Pocahontas (Mrs. John Rolfe), who were allowed to be classed as 'whites':
The 'Pocahontas Exception' to Virginia's 1924-1975 Racial Identity Act
"Exempted from this racial policing regime were those influential whites, the First Families of Virginia, who proudly claimed Native American ancestry from Pocahontas."