The Compromise of 1850 established harsher fugitive slave laws that turned many Northerners against slavery and strengthened the abolitionist movement. Tensions further increased over the Kansas-Nebraska Act and "Bleeding Kansas", the 1856 election of Republican Lincoln, and the Dred Scott decision allowing the expansion of slavery into new territories. By 1860 the nation was polarized, leading Southern states to secede after Lincoln's election but before he took office, forming the Confederate States of America.