White Virginians had long been concerned with policing the color line. Virginia outlawed interracial marriage in 1691. In 1705 the colony defined a "mulatto" as "the child of an Indian and the child, grand child, or great grand child, of a negro," and in 1785 the commonwealth clarified that definition to apply to "every person who shall have one-fourth part or more of negro blood." After the American Civil War (1861–1865), a new statute defined a "colored person" as anyone having one-fourth or more of "negro blood" and an Indian as any person having one-fourth or more of Indian blood. In the first years of the twentieth century, with the emergence of scientific racism (the use of purportedly scientific methods to justify racial differences and hierarchies) and its attendant policies of segregation and disfranchisement, white Virginians sought to tighten racial definitions. In 1910, the Virginia General Assembly declared that anyone with one-sixteenth or more "black blood" was black. All other people were legally white.

Such quasi-scientific, genealogical measurements characterized many states' efforts to define race, but the Virginia General Assembly also enlisted the power of the state to enforce such racial categories. In 1912, the General Assembly created the Bureau of Vital Statistics to register all births, deaths, and marriages in the state, and all birth certificates had to state the race of the parents. Under the direction of Dr. Walter Plecker, the Bureau of Vital Statistics became an active agent in policing the color line. By the early 1920s, many white Virginians, including Plecker, believed the 1910 law had failed to defend their prerogatives.

Disdaining the Ku Klux Klan's violent white supremacist policies and tactics, elite white Virginians embraced the scientific racism espoused by the Anglo-Saxon Clubs of America. Founded in Richmond in September 1922 by internationally renowned pianist John Powell, self-styled ethnologist Earnest Sevier Cox, and Plecker, the ASCOA committed itself to preserving white "racial purity." Powell provided the movement's star power and publicity; Cox's book White America (1923) provided the pseudoscientific, eugenic justifications; and Plecker backed the other two with the state's police power. The ASCOA demanded legislation prohibiting interracial marriage and defining anyone with any non-white heritage—even one drop—as black.

The ASCOA's rhetoric decrying race-mixing angered powerful Virginia families that claimed descent from Pocahontas and John Rolfe. Thus, the ASCOA's racial integrity bill was amended to allow the marriage of whites with anyone having less than one-sixteenth Native American blood—a fraction of "Indian" heritage that preserved these families' whiteness. This became known as the "Pocahontas clause." Legislators passed the amended RIA to wide acclaim and Plecker began zealously enforcing the act.

Plecker believed that Virginia's Indians had thoroughly interbred with African Americans, rendering all "modern" Indians—especially those in Amherst and Rockbridge counties—black. Plecker instructed local registrars to affix a warning label to the birth certificates of people claiming Indian heritage; the label stated that the person was "colored" and provided genealogical information. Plecker also ordered registrars to refuse marriage licenses to anyone with any trace of non-white blood attempting to marry a white person. He personally threatened anyone who questioned the system. Plecker's actions prompted lawsuits from people contesting their racial classification and demanding the right to marry.

The first two lawsuits challenging the RIA resulted in opposite decisions, drawing the law's constitutionality into question. The first case upheld the RIA. In the second case, however, the same judge ruled that since there was no discernable trace of non-white blood in either party, the couple should be allowed to marry.

Rather than appeal the ruling, and risk having the RIA declared unconstitutional, the ASCOA sought to tighten the law's racial classifications. Attempted revisions failed in 1926 and 1928, although a law mandating racial segregation at all public assemblages passed in 1926 with ASCOA support. Many whites believed that these measures, combined with Plecker's rigorous policing, unnecessarily inflamed racial tensions. Nevertheless, a threat to segregated public schooling precipitated further legislation.

Since the RIA did not amend the 1910 act defining people with more than one-sixteenth black "blood" as black, individuals with less than one-sixteenth black blood slipped through a legal loophole. According to the RIA, these people were not white enough to marry white people; yet according to the 1910 law they were not black. Therefore, by law, these "colored" people had to attend white schools.

To defend white privilege, the General Assembly passed another racial integrity law in 1930. Under this statute, people with one-quarter Indian blood and less than one-sixteenth black blood were classified as Indians—but only if they lived on a reservation, segregated from whites. Anyone else with even "one drop" of non-white blood was henceforth black—unless exempted by the RIA's "Pocahontas clause." This meant that the Indians of Amherst and Rockbridge counties became black by law.

Virginia's RIA remained in force until the U.S. Supreme Court declared it unconstitutional in Loving v. Virginia (1967). Virginia's Monacan Indians have continued to battle their 1924 legislative reclassification as non-Indian, seeking tribal recognition from the federal government.