However, in 1876 after several brutal wars, the Sioux, Cheyennes, Arapahos, Kiowas, and Comanches complied to move to certain areas where whites were prohibited (Greenberg 33). After more than a decade of vile treatment by whites, Indians of California and Nevada agreed to settle on reservations (Document 46). Though the barbarous mistreatment of Indians had died somewhat, racial discrimination was still evident in the segregation of Indian land and true American land. Not only did white Americans consider themselves racially and culturally superior to Indians, but they also shared obvious discrimination towards other minority groups. There was nothing "free " about the establishment of the American nation (Greenberg 37). Racial disputes were also aggravated by James K. Polk in the war with Mexico, which started in 1846. According to Greenberg, " U.S. soldiers committed atrocities in Mexico, including the rape and murder of civilians, which horrified not only Mexicans but also the soldiers' own commanding officers and American civilians back home " (Greenberg 24). In 1848, the Treaty of Guadalupe Hidalgo was signed, exchanging 50,000 square miles of Mexican land to the U.S. for 15 million dollars. Regardless of the promised citizenship rights to Mexican Americans in the treaty, racism towards this minority group was still firmly implanted (Greenberg 25). After the war, filibustering, another tactic of U.S. territorial expansion, was also driven against Spanish Florida, Mexican Texas, Canada, and parts of the Caribbean Islands. Sectionalism pursued through the 1840s and 1850s as a redundant narrow " minded concern, resulting from the condition of slavery. According to Greenberg, "in order to ˜prove' that Anglo " Saxons were destined to dominate lesser races, leading scientists of the antebellum era, many from the South, posited theories of racial difference that expanded on earlier ideas of a racial hierarchy " (Greenberg 18).