john c. fremont(US) won attacks by land and sea in cali. zachary taylor defeated large forces in mexico. mexicans refused to negotiate, so president polk ordered forces led by winfield scott into mexico city. treaty of guadalupe hidalgo in 1848 ended the war, giving the Us land originally sought by slidell (new mexico, arizna, cali, texas, and parts of colorado, utah, and nevada). border set at rio grande river. raised questions of slavery in the new territory. raised questions of slavery in the new territory. henry david thoreau and a young whig, abraham lincoln, opposed the war. Supreme Court case involving a slave, Scott, who was taken by this master from Missouri, a slave state, to Illinois, a free state. After Scott had been returned to Missouri, he sued for freedom for himself and his family, stating that by residing in a free state he had ended his slavery. President Buchanan meant for the cases's decision to serve as the basis for the slavery issue. Prosouthern judge Taney ruled the Scott did not have the right of citizenship, which he would need to be able to bring forth a suit. Ruled further that the Missouri compromise itself was unconstitutional because congress had no power to prohibit slavery in the territories, as slaves were property. The Scott decision would apply to all African American who were regarded as inferior, and therefore without rights. emmett till, a teenage AA, was kiled by two whites after supposedly whistling at one of their wives; the men were acquitted. in 1960 four AA students in Greensboro, NC sat at the woolworth's "whites only" lunch counter and refused to leave until they were served, sparking sit-ins throughout the south. an explosion at the baptist church in birmingham, alabama, killed four AA girls (1963). during a voter registration drive in mississippi, two white college students and a local AA were murdered, civil rights legislation resulted. in 1965, a group marched from selma, alabama, to birmingham, alabama, for voting rights; the 1965 voting rights act was signed soon thereafter.