The Republican party was one of two new parties to emerge between 1854 and 1856 to challenge Whigs for their role as primary opponent of Democrats. Spawned by northern outrage at the Kansas-Nebraska Act of 1854 which reopened the possibility of slavery's westward spread and committed to defeating Democrats in order to drive the so-called southern Slave Power from control of the national government, the Republicans attracted hundreds of thousands of former Democrats, Whigs, and Free Soilers in the North. Lincoln, who clung to the Whig party in 1854, would join the Republicans in 1856, and he received votes for the new party's vice presidential nomination that year when the party chose a ticket of John C. Fremont and William L. Dayton. Exploiting northern anger at events in Kansas and the caning of Republican Senator Charles Sumner in the Senate chamber. Republicans carried eleven of sixteen free states in 1856, thereby establishing themselves as the successor to the Whigs, even though they had almost no support in any slave state other than Missouri. Between 1856 and 1860 the party would benefit from northern voters' dismay at actions of Democratic President James Buchanan's administration, especially his attempt to force Kansas's admission to the Union as a slave state under the Lecompton Constitution. But to enhance their chances to carry the three crucial states of the lower North that Fremont had failed to carry in 1856—Illinois, Indiana, and Pennsylvania—Republicans in 1860 would bypass their most well-known leader and give their presidential nomination to Abraham Lincoln.