Causes of the War

Westward Expansion

In the early decades of the nineteenth century, most white Northerners and Southerners agreed wholeheartedly that the Western territories should be settled by Americans, and that moving Indians to reservations and making their land available to white settlers was God’s plan, or the nation’s “manifest destiny.” This sense of entitlement is powerfully portrayed by William S. Jewett in his monumental 1850 painting The Promised Land—The Grayson Family, which also represents the optimism and aspirations of many Americans, Northern and Southern, who moved west in search of a better life. Sharp differences arose, however, over whether the new society created in the West would be free of slavery or not.


<em>The Promised Land&mdash;The Grayson Family</em>

The Promised Land—The Grayson Family

When the United States gained more territory during the War with Mexico (1844–1846), the question of how to handle slavery in those newly gained lands grew even more pressing. This prompted the development of another form of anti-slavery politics: “free soil,” in which people—mostly Northerners—opposed the expansion of slavery into the Western territories. Southerners viewed free soil as a dangerous doctrine primarily because the more free states that were admitted to the Union, the more unequal slave states’ representation in Congress would become. Southerners believed that if they were outnumbered in Congress, laws could be passed to abolish slavery in the South, even though free soilers denied that this was their intention.

<em>Daniel Webster</em>

Daniel Webster

Many Southerners also distrusted the alternative policy of popular sovereignty, in which the people who settled the territories of the West would be allowed to decide for themselves whether their new state would or would not allow slavery. Congress attempted to establish popular sovereignty as the law of the land in the Compromise of 1850, authored and passed through the efforts of Senators Daniel Webster, Henry Clay, and Stephen Douglas. The sculpture Daniel Webster by Thomas Ball, created in 1853 and sold for display in people’s homes, attests to the politician’s popularity among many Northerners. The dignified portrait of Stephen Arnold Douglas, painted by Louis O. Lussier around 1861, signals his importance as well.

<em>Stephen Arnold Douglas</em>

Stephen Arnold Douglas

Experiments with popular sovereignty in Kansas, however, convinced many Southerners that non-slaveholding farmers would quickly move into and dominate new territories. In response, Southerners began to insist that Congress pass laws to protect slavery in the West. 

Many Northerners also distrusted popular sovereignty because of what they called the “slave power conspiracy.” They believed that slaveholders were unfairly influencing free state politicians to do things that protected slaveholders, but that did not respect the rights of white, non-slaveholding Northerners. Indeed, opposition to popular sovereignty drove free soil Northerners to found the Republican Party in 1854 to protest the extension of slavery into the West.