How white do you have to be to deserve rights? Are you white enough? Can you prove it?

Biologically speaking, of course, all humans belong to a single race. Despite the science, superficial distinctions such as skin pigmentation and social graces are still used to create a sense of separation among people. These variations among people and the terms attached to them are so ingrained in American thought that author Ariela Gross is forced to open her book, What Blood Won't Tell, with a note about the terminology used to trace the legal history of attempts to define race.

Gross opens with the story of Alexina Morrison, a slave in Louisiana who escaped from James White in 1857 and sought help from law enforcement. Normally a runaway slave would have been immediately returned to her ‘owner,’ but Alexina’s white knight took her home and “introduced her into white society, eventually taking her to balls and other amusements with his family.” Furthermore, when Alexina sued her slaveholder for her freedom, she enjoyed the support of the townsfolk. Anyone who knows the tiniest bit of U.S. history will likely be amazed by the liberal and enlightened behavior of so many people toward Alexina, but there is a simple if contemptible explanation – Alexina was a blue-eyed blond. Her defenders were not standing up for human rights, but for the rights of a white woman.

The issue upon which Alexina’s freedom turned was race. Was she white and therefore naturally entitled to human rights, or was she ‘colored’ and the legal property of James White? Defense and prosecution alternately argued that her behavior was or was not white, that she did or did not fit in to white society, and even presented as evidence the traits and actions that ‘everyone knows’ are or are not indicative of whiteness. Over the course of Alexina’s three trials, it was never the moral and ethical question of enslaving human beings that came into evidence; both sides were seeking the judges’ rulings on the definition of Caucasian.

The case of Alexina Morrison should have brought all involved to the realization that arbitrary indicators of race are a slippery slope to climb, yet the subject still hasn’t been laid to rest. What Blood Won't Tell chronicles the history of efforts to determine racial identity in the courts. Seldom, if ever, does science enter into the effort; rather, attorneys and others turn their attention to the evidence of skin color, social behavior, cultural customs, and other subjective and changeable evidence. The only thing that remains constant is the underlying assumption that white equals “full social and political citizenship” while anything else is inferior, less-than, and undeserving of Constitutional protection.

Gross includes high points in the struggles of various groups – Native Americans, Asian Americans, Hawai’ians, Mexican Americans, and various combinations — to claim their legal, civil, and human rights either by ‘passing’ as white or by emphasizing their difference from other non-white groups. The overriding opinion was that it’s best to be white, but if you can’t manage that, just don’t be black. This shameful and ignorant American caste system is still as deeply entrenched in the nation’s consciousness as ever, it seems.

What Blood Won't Tell is packed with landmark cases that grow increasingly convoluted as each court attempts to sort through the tangled threads of racial identity. Gross, a Professor of Law and History at the University of Southern California, presents here in compact form a timeline of attempts to determine the basis of something that doesn’t exist and accentuates the absurdity of racial discrimination. Never bogged down in too much legalese, What Blood Won't Tell turns out to be a riveting overview of legal decisions regarding race and freedoms and a dizzying look at the insanity of social hierarchy and its ongoing impact on social development.