Slavery and the Road to Civil War, 1820-1861

As America expanded west, every new territory forced a confrontation with the question that had been avoided since 1787: would slavery be permitted to spread?

The "Cotton Kingdom":

By the 1840s, cotton was King in the South. The invention of the cotton gin (1793) had made large-scale cotton farming enormously profitable — but only with slave labour. By 1860, the South had nearly 4 million enslaved people, and cotton accounted for 60% of all US exports. Southern planters viewed slavery not merely as an economic system but as the foundation of their entire civilisation.

The Missouri Compromise, 1820:

When Missouri applied for statehood as a slave state, it threatened to upset the balance in the Senate. The compromise drew a line at 36°30' N latitude: slavery would be permitted south of the line, banned north of it. Missouri entered as a slave state, Maine as a free state. The compromise preserved the Union for thirty years — but it was a temporary fix, not a solution.

Bleeding Kansas, 1854-1859:

The Kansas-Nebraska Act (1854) repealed the Missouri Compromise, applying "popular sovereignty" — letting settlers in each territory vote whether to allow slavery. Pro-slavery and anti-slavery settlers flooded into Kansas to tip the vote. The result was a vicious guerrilla war: abolitionist John Brown led a massacre of pro-slavery settlers at Pottawatomie Creek (1856); pro-slavery forces sacked the anti-slavery town of Lawrence. "Bleeding Kansas" showed that slavery could not be settled peacefully.

Lincoln's Election and Secession, 1860-1861:

When the Republican Abraham Lincoln won the 1860 presidential election without carrying a single southern state — on a platform of restricting (not abolishing) slavery's spread — southern states read it as an existential threat. South Carolina seceded in December 1860. By February 1861, seven states had left, forming the Confederate States of America. When Confederate forces attacked Fort Sumter in April 1861, the Civil War began.