The Sectional Conflict: From Compromise to Civil War

Until the middle of the nineteenth century, sectional differences over slavery were managed through compromise or avoidance.
The Northwest Ordinance of 1787 barred slavery from the Old Northwest ( $Ohio$ , $Indiana$ , $Illinois$ , $Michigan$ , and $Wisconsin$ ) with little Southern resistance, partly due to the ambivalence of Virginian slaveholders like Thomas Jefferson.
At the Constitutional Convention, the $\frac{3}{5}$ clause was a compromise to balance Southern representation and taxation; delegates also agreed to a $20$ -year ban on interfering with the international slave trade but avoided taking a firm stand on slavery's permanent status.
The Missouri Compromise ( $1820$ ) maintained sectional parity in the Senate by admitting Maine as a free state and Missouri as a slave state, while banning slavery in the Louisiana Purchase north of the southern border of Missouri ( $36^{\circ} 30'$ \text{ line}).
The Nullification Crisis ( $1832$ ) saw South Carolina, influenced by John C. Calhoun, challenge the Tariff of Abominations ( $1828$ ). A reduction in the tariff averted military conflict, but the question of ultimate federal vs. state authority remained unsettled.

Manifest Destiny provided a religious and material justification for westward expansion, appealing to Northern industrialists and Southern planters alike.
Conflict arose over the status of land acquired after the Mexican War ( $1846$ - $1848$ ). The Treaty of Guadalupe Hidalgo saw the U.S. pay Mexico $15 \text{ million dollars}$ for territories including California and the New Mexico and Utah territories.
The Free-Soil ideology emerged in the North, viewing slavery as a threat to the " $\text{free labor}$ ideal," which ennobled work as the basis for upward mobility. Conversely, the South evolved into an aristocratic society where labor was viewed as degrading and fit only for enslaved people.
Southern ideologues like George Fitzhugh and John C. Calhoun began defending slavery as a " $\text{positive good}$ " and a stabilizing force compared to Northern industrial capitalism.

The Compromise of 1850 was the final major effort to manage conflict. It admitted California as a free state, established a stricter Fugitive Slave Law, and banned the slave trade in Washington D.C.
The Kansas-Nebraska Act ( $1854$ ), introduced by Stephen Douglas, applied " $\text{popular sovereignty}$ " to new territories, effectively rescinding the Missouri Compromise. This led to the collapse of the Whig Party and the birth of the Republican Party.
"Bleeding Kansas" saw violent clashes between pro-slavery and free-soil settlers, including John Brown's raid at Pottawatomie. This violence reached the Senate floor with the caning of Charles Sumner by Preston Brooks.
The Dred Scott decision ( $1857$ ) ruled the Missouri Compromise unconstitutional, declared that African-Americans had no rights that whites were bound to respect, and suggested slavery could not be prohibited in territories.

The Panic of 1857 caused a depression in the North but left the South mostly unaffected due to high cotton prices. This convinced Southern " $\text{fire-eaters}$ " that the South could thrive as an independent nation.
The Republican Party Platform of $1856$ and $1860$ appealed to various Northern interests by supporting free soil, an increased tariff, a Homestead Act, and federal subsidies for railroads.
In the 1860 presidential election, the Democratic Party split between Stephen Douglas and John C. Breckinridge. Abraham Lincoln won the presidency with no Southern support.
Feeling marginalized by the shift in political power and the Northern commitment to anti-slavery, South Carolina led the Southern states in seceding from the Union, ultimately resulting in the War Between the States in $1861$ .