the abolition of apartheid in South Africa in 1991, followed by that country's first multiracial elections in 1994). United States Early history White supremacy was dominant in the United States both before and after the American Civil War, and it persisted for decades after the Reconstruction Era. Prior to the Civil War, many wealthy White-European Americans owned slaves; they tried to justify their economic exploitation of Black people by creating a "scientific" theory of White superiority and Black inferiority. One such slave owner, future president Thomas Jefferson, wrote in 1785 that Blacks were "inferior to the whites in the endowments of body and mind." In the antebellum South, four million slaves were denied freedom. The outbreak of the Civil War saw the desire to uphold white supremacy being cited as a cause for state secession and the formation of the Confederate States of America. In an editorial about Native Americans and the American Indian Wars in 1890, author L. Frank Baum wrote: "The Whites, by law of conquest, by justice of civilization, are masters of the American continent, and the best safety of the frontier settlements will be secured by the total annihilation of the few remaining Indians." The Naturalization Act of 1790 limited U.S. citizenship to whites only. In some parts of the United States, many people who were considered non-white were disenfranchised, barred from government office, and prevented from holding most government jobs well into the second half of the 20th century. Professor Leland T. Saito of the University of Southern California writes: "Throughout the history of the United States, race has been used by whites for legitimizing and creating difference and social, economic and political exclusion." 20th century The denial of social and political freedom to minorities continued into the mid-20th century, resulting in the civil rights movement. The movement was spurred by the lynching of Emmett Till, a 14-year-old boy. David Jackson writes it was the image of the "murdered child’s ravaged body, that forced the world to reckon with the brutality of American racism." Vann R. Newkirk| wrote "the trial of his killers became a pageant illuminating the tyranny of white supremacy." Moved by the image of Till's body in the casket, one hundred days after his murder Rosa Parks refused to give up her seat on a bus to a white person. Sociologist Stephen Klineberg has stated that U.S. immigration laws prior to 1965