The 1854 congressional elections exacerbated sectional tensions by bringing representatives from a strictly northern party—the Republicans—into Congress. But the conflicts over slavery reached far beyond the nation’s capital. After passage of the Kansas-Nebraska Act, advocates and opponents of slavery poured into Kansas in anticipation of a vote on whether the state would enter the Union slave or free.

As Kansas prepared to hold its referendum, settlers continued to arrive daily, making it difficult to determine who was eligible to vote. In 1855 Southerners installed a proslavery government at Shawnee Mission, while abolitionists established a stronghold in Lawrence. Violence erupted when proslavery settlers invaded Lawrence, killing one resident, demolishing newspaper offices, and plundering shops and homes. Fearing that southern settlers in Kansas were better armed than antislavery Northerners in the territory, eastern abolitionists raised funds to ship rifles to Kansas.

In 1856 longtime abolitionist John Brown carried his own rifles to Kansas. Four of his sons already lived in the territory. To retaliate for proslavery attacks on Lawrence, the Browns and two friends kidnapped five proslavery advocates from their homes along Pottawatomie Creek and hacked them to death. The so-called Pottawatomie Massacre infuriated southern settlers, who then drew up the Lecompton Constitution, which declared Kansas a slave state. President Pierce made his support of the proslavery government clear, but Congress remained divided. While Congress deliberated, armed battles continued. In the first six months of 1856, another two hundred settlers—on both sides of the conflict—were killed in what became known as Bleeding Kansas

Fighting also broke out on the floor of Congress. Republican senator Charles Sumner of Massachusetts delivered an impassioned speech against the continued expansion of the Slave Power. He launched scathing attacks on planter politicians like South Carolina senator Andrew Butler. Butler’s nephew, Preston Brooks, a Democratic member of the House of Representatives, rushed to defend his family’s honor. He assaulted Sumner in the Senate chamber, beating him senseless with a cane. Sumner, who never fully recovered from his injuries, was considered a martyr in the North. Meanwhile Brooks was celebrated throughout South Carolina.

The presidential election of 1856 began amid an atmosphere poisoned by violence and recrimination. The Democratic Party nominated James Buchanan of Pennsylvania, a proslavery advocate. Western hero John C. Frémont headed the Republican Party ticket. The American Party, in its final presidential contest, selected former president Millard Fillmore as its candidate. The strength of nativism in politics was waning, however, and Fillmore won only the state of Maryland. Meanwhile Frémont attracted cheering throngs as he traveled across the nation. Large numbers of women turned out to see Jessie Frémont, the first presidential candidate’s wife to play a significant role in a campaign. Frémont carried most of the North and the West. Buchanan captured the South along with Pennsylvania, Indiana, and Illinois. Although Buchanan won only 45.2 percent of the popular vote, he received a comfortable majority in the electoral college, securing his victory. The nation was becoming increasingly divided along sectional lines, and President Buchanan would do little to resolve these differences.