How to Understand the Causes of the Civil War

While it’s an oversimplification to say that the American Civil War was only about slavery, this Southern institution did touch on all the major events leading to the war. Essentially, the issue of slavery became bound up with the issue of states' rights—and the issue of states' rights was what caused the South to secede in 1861. Here's a quick sketch of the historical trends that set the Civil War in motion.

Instructions

Difficulty: Easy

1. A delicate balance existed between slave states and free states. As the U.S. pushed westward in the early 19th century, the division of power between slave states and free states became an increasingly divisive issue: slave states, especially, were concerned that the admission of new free states into the Union should be counterbalanced by the admission of new slave states. As early as 1820, Congress passed the Missouri Compromise, which permitted slavery south of a certain boundary in the western territories, and banned it to the north.
2. The Northern states had more dynamic economies. Throughout the early 1800s, the American Northeast became increasingly industrialized, while the Southern states had more settled plantation economies. As a result, some Northern politicians felt that the U.S. economic engine was, under the balance-of-power scheme, at the mercy of Southern votes—while Southerners felt they were at the mercy of (and patronized by) the burgeoning Northern power.
3. The abolitionist movement ruffled Southern feathers. Ever since the founding of the U.S., the Northern states had been uncomfortable with slavery (even though many of the Founding Fathers were slaveholders). This discomfort grew more intense in the 1840s and 1850s, when an increasing number of religious revivalists in the North branded slavery as an outright evil. As a result, many Northerners refused to return escaped slaves to their Southern owners—and Southerners interpreted this as a blatant illegality just short of a declaration of war.
4. The new Republican Party sectionalized the two-party system. The Republican Party was founded in 1854 as a reaction to the Kansas-Nebraska Act, which Northerners feared would allow slavery to spread into Kansas from its Southern neighbor. The Republicans' opposition to slavery caused Southerners to flock to the Democratic Party (and, in the 1860 election, to split off from the Democrats because of their perceived softness on the Kansas issue).
5. The election of Abraham Lincoln prompted the Southern states to secede. With a Republican in office, Southern leaders felt the balance of power had been altered irrevocably, and that it would only be a matter of time before the North imposed its antislavery policies (thus bulldozing over what Southerners perceived to be states' rights). As a result, South Carolina was the first state to secede from the Union, shortly followed by most of the other states south of the Mason-Dixon line.