According to the one drop rule adopted by many US southern states, if you have one drop of African blood, you are black. Therefore, we are all black, because our ancestors all came from Africa.
"The one-drop rule was a tactic in the U.S. South that codified and strengthened segregation and the disfranchisement of most blacks and many poor whites from 1890-1910. After Supreme Court decisions in Plessy v. Ferguson and related matters, White-dominated legislatures felt free to enact Jim Crow laws segregating Blacks in public places and accommodations, and passed other restrictive legislation. Legislatures sought to prevent interracial relationships to keep the white race "pure", long after slaveholders and overseers took advantage of enslaved women and produced the many mixed-race children.
The 1910–19 decade was the nadir of the Jim Crow era. Tennessee adopted a one-drop statute in 1910, and Louisiana soon followed. Then Texas and Arkansas in 1911, Mississippi in 1917, North Carolina in 1923, Virginia in 1924, Alabama and Georgia in 1927, and Oklahoma in 1931. During this same period, Florida, Indiana, Kentucky, Maryland, Missouri, Nebraska, North Dakota, and Utah retained their old "blood fraction" statutes de jure, but amended these fractions (one-sixteenth, one-thirtysecond) to be equivalent to one-drop de facto.
Madison Grant of Virginia in The Passing of the Great Race wrote: "The cross between a white man and an Indian is an Indian; the cross between a white man and a ***** is a *****; the cross between a white man and a Hindu is a Hindu; and the cross between any of the three European races and a Jew is a Jew."
In the case of Native American descendants with whites, the one-drop rule of definition was extended only so far as those with more than one-sixteenth Indian blood, due to what was known as the "Pocahontas exception." The "Pocahontas exception" existed because many influential Virginia families claimed descent from the American Indian Pocahontas of the colonial era. To avoid classifying such people as non-white, the Virginia General Assembly declared that a person could be considered white so long as he or she had no more than one-sixteenth Indian "blood".
Walter Plecker of Virginia and Naomi Drake of Louisiana insisted on trying to label families of mixed ancestry as Black. In 1924, Plecker wrote, "Two races as materially divergent as the White and *****, in morals, mental powers, and cultural fitness, cannot live in close contact without injury to the higher." A subtext to this concept was the assumption that Blacks were somehow "improved" through White intermixture.
When the U.S. Supreme Court outlawed Virginia's ban on inter-racial marriage in Loving v. Virginia (1967), it declared Plecker's Virginia Racial Integrity Act and the one-drop rule unconstitutional."