During the 1850s, sectional differences within the United States, largely about slavery, grew wider as the country's leaders debated whether to allow slavery to expand into the western territories and as criticism of slavery intensified in some free states. The Compromise of 1850 had temporarily settled some of the sectional divisions, but it did not solve the problems that resulted from the existence of slavery in part of the nation. Some of the county's principal Protestant denominations divided into northern and southern branches during the 1840s and 1850s. Critics of slavery became more numerous in the free states, and during the 1850s a once-small group of committed abolitionists attracted new followers. At the same time many defenders of slavery adopted a radical proslavery set of beliefs that made compromise between the extreme opponents of slavery and its most extreme defenders ever more difficult. The problems that the sectional crisis posed for Virginians and for Americans generally made their futures uncertain.
For decades before 1850, many men and women who escaped from slavery were able to avoid being captured and returned to their owners, but the Fugitive Slave Act, part of the Compromise of 1850, empowered federal officials to assist owners seeking to reclaim runaway slaves.
Settlement of the Great Plains increased rapidly during the 1850s, even while many people moved into Texas and other portions of the territory acquired as a result of the war with Mexico in the 1840s. Congress repeatedly debated whether slavery should be allowed into those large territories that were not yet organized into states.
In October 1859 John Brown and other antislavery men slipped across the border between Maryland and Virginia and occupied the United States arsenal at Harpers Ferry. Brown hoped to arm enslaved men and lead a campaign to abolish slavery.