From the article “Black and White World: Why race still matters in Obama’s America”

 Gross zeros in on one revealing byproduct of the system of racialized citizenship: the legal fight of nonwhite citizens not to be counted as black under the infamous “one drop” rule of racial categorization—a stigma that could lock them out of all sorts of social benefits, from business contracts to rights of inheritance and land ownership. These so-called race identity trials offer a prism, Gross argues, that permits us to “observe the changing meanings of race throughout our history, and the changes and continuities in racism itself.”