identities are defined today (blood quantum versus one-drop and political assumptions) have been based on different historical circumstances. According to the anthropologist Gerald Sider, such racial designations were a means to concentrate power, wealth, privilege and land in the hands of Whites in a society of White hegemony and privilege. The differences had little to do with biology and more to do with the history of slavery and its racism, and specific forms of white supremacy (the social, geopolitical and economic agendas of dominant Whites vis-à-vis subordinate Blacks and Native Americans). They related especially to the different social places which Blacks and Amerindians occupied in White-dominated 19th-century America. Sider suggests that the blood quantum definition of Native American identity enabled mixed-race Whites to acquire Amerindian lands during the allotment process. The one-drop rule of Black identity, enforced legally in the early 20th century, enabled Whites to preserve their agricultural labor force in the South. The contrast emerged because, as peoples transported far from their land and kinship ties on another continent, they became reduced to valuable commodities as agricultural laborers. In contrast, Amerindian labor was more difficult to control; moreover, Amerindians occupied large territories that became valuable as agricultural lands, especially with the invention of new technologies such as railroads. Sider thinks the blood quantum definition enhanced White acquisition of Amerindian lands in a doctrine of manifest destiny, which subjected Native Americans to marginalization and resulted in numerous conflicts related to American expansionism. The political economy of the race had different consequences for the descendants of aboriginal Americans and African slaves. The 19th century blood quantum rule meant that it was relatively easier for a person of mixed Euro-Amerindian ancestry to be accepted as White. The offspring of a few generations of intermarriage between Amerindians and Whites likely would not have been considered Amerindian (at least not in a legal sense). Amerindians could have treaty rights to land, but because an individual with only one Amerindian great-grandparent no longer was classified as Amerindian, he lost a legal claim to Amerindian land, under the allotment rules of the day. According to Sider's theory, Whites were more easily able to acquire Amerindian lands. On the other hand, the same individual who could be denied legal standing in a tribe, according to the government, because he was "too White" to claim property rights, might still have enough visually identifiable Amerindian ancestry to be