Top Causes of the Civil War

American Civil War
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The U.S. Civil War lasted from 1861 to 1865 and led to over 618,000 casualties. Its causes can be traced back to tensions that formed early in the nation's history. While the issue of slavery was at the heart of the division between North and South, a complex array of issues led to the South's secession and the "War Between the States."

Economic and Social Differences

When Eli Whitney invented the cotton gin in 1793, cotton became very profitable.

This machine was able to reduce the time it took to separate seeds from the cotton. At the same time, the increase in the number of plantations willing to move from other crops to cotton meant the greater need for a large amount of cheap labor such as slaves. The southern economy became a one-crop economy, depending on cotton and therefore on slavery.

Though it was often supported throughout the social and economic classes, not every Southerner owned slaves. The population of the South was around 6 million in 1850 and only about 350,000 were slave owners. This included many of the wealthiest families, a number of whom owned large plantations.

In contrast, industry ruled the economy of the North and less emphasis was on agriculture, though even that was more diverse. Many northern industries were purchasing the South's raw cotton and turning it into finished goods.

The North saw a population boom as industrialization took over as well.

The birth rate was greater than in the South and it was a great time for immigration. It's said that seven of eight immigrants settled in the North and many of their traditional beliefs looked negatively on slavery.

This disparity between the two regions of the country set up a major difference in economic attitudes.

The South was based on the plantation system while the North was focused on city life. This change in the North meant that society evolved as people of different cultures and classes had to work together. The South continued to hold onto an antiquated social order. On both sides, economics influenced people's political views.

States vs. Federal Rights

Since the time of the American Revolution, two camps emerged when it came to the role of government. Some people argued for greater rights for the states and others argued that the federal government needed to have more control.

The first organized government in the U.S. after the Revolution was under the Articles of Confederation. The thirteen states formed a loose confederation with a very weak federal government. However, when problems arose, the weaknesses of the Articles caused the leaders of the time to come together at the Constitutional Convention and create, in secret, the U.S. Constitution.

Strong proponents of states rights like Thomas Jefferson and Patrick Henry were not present at this meeting. Many felt that the new constitution ignored the rights of states to continue to act independently. They felt that the states should still have the right to decide if they were willing to accept certain federal acts.

This resulted in the idea of nullification, whereby the states would have the right to rule federal acts unconstitutional. The federal government denied states this right. However, proponents such as John C. Calhoun—who resigned as Vice President to represent South Carolina in the Senate—fought vehemently for nullification. When nullification would not work and many of the southern states felt that they were no longer respected, they moved towards thoughts of secession.

Slave and Non-Slave States

As America began to expand—first with the lands gained from the Louisiana Purchase and later with the Mexican War—the question arose of whether new states would be slave or free. An attempt was made to ensure that equal numbers of free and slave states were admitted to the Union, but over time this proved difficult.

The Missouri Compromise passed in 1820. This established a rule that prohibited slavery in states from the former Louisiana Purchase north of the latitude 36 degrees 30 minutes, with the exception of Missouri. 

During the Mexican War, the debate began about what would happen with the new territories the U.S. expected to gain upon victory. David Wilmot proposed the Wilmot Proviso in 1846 which would ban slavery in the new lands. This was shot down to much debate.

The Compromise of 1850 was created by Henry Clay and others to deal with the balance between slave and free states. It was designed to protect both northern and southern interests. When California was admitted as a free state, one of the provisions was the Fugitive Slave Act. This held individuals responsible for harboring fugitive slaves even if they were located in non-slave states. 

The Kansas-Nebraska Act of 1854 was another issue that further increased tensions. It created two new territories that would allow the states to use popular sovereignty to determine whether they would be free or slave. The real issue occurred in Kansas where pro-slavery Missourians, called "Border Ruffians," began to pour into the state in an attempt to force it toward slavery. 

Problems came to a head with a violent clash at Lawrence, Kansas, causing it to become known as "Bleeding Kansas." The fight even erupted on the floor of the Senate when anti-slavery proponent Charles Sumner was beaten over the head by South Carolina's Senator Preston Brooks.

The Abolitionist Movement

Increasingly, Northerners became more polarized against slavery. Sympathies began to grow for abolitionists and against slavery and slaveholders. Many in the North came to view slavery as not just socially unjust, but morally wrong.

The abolitionists came with a variety of viewpoints. Those such William Lloyd Garrison and Frederick Douglass wanted immediate freedom for all slaves. A group that included Theodore Weld and Arthur Tappan advocated for emancipating slaves slowly. Still others, including Abraham Lincoln, simply hoped to keep slavery from expanding.

A number of events helped fuel the cause for abolition in the 1850s. Harriet Beecher Stowe wrote "Uncle Tom's Cabin" and that popular novel opened many eyes to the reality of slavery. The Dred Scott Case brought the issue of a slave's rights, freedom, and citizenship to the Supreme Court.

Additionally, some abolitionists took a less peaceful route to fighting slavery. John Brown and his family fought on the anti-slavery side of "Bleeding Kansas." They were responsible for the Pottawatomie Massacre in which they killed five settlers who were pro-slavery.  Yet, Brown's best-known fight would be his last when the group attacked Harper's Ferry in 1859, a crime for which he would hang.

The Election of Abraham Lincoln

The politics of the day were as stormy as the anti-slavery campaigns. All of the issues of the young nation were dividing the political parties and reshaping the established two-party system of Whigs and Democrats.


The Democratic party was divided between factions in the North and South. At the same time, the conflicts surrounding Kansas and the Compromise of 1850 transformed the Whig party into the Republican party (established in 1854). In the North, this new party was seen as both anti-slavery and for the advancement of the American economy. This included the support of industry and encouraging homesteading while advancing educational opportunities. In the South, Republicans were seen as little more than divisive.

The presidential election of 1860 would be the deciding point for the Union. Abraham Lincoln represented the new Republican party and Stephen Douglas, the Northern Democrat, was seen as his biggest rival. The Southern Democrats put John C. Breckenridge on the ballot. John C. Bell represented the Constitutional Union Party, a group of conservative Whigs hoping to avoid secession.

The country's divisions were clear on election day. Lincoln won the North, Breckenridge the South, and Bell the border states. Douglas won only Missouri and a portion of New Jersey. It was enough for Lincoln to win the popular vote as well as 180 electoral votes.

Even though things were already near a boiling point after Lincoln was elected South Carolina issued its "Declaration of the Causes of Secession" on December 24, 1860. They believed that Lincoln was anti-slavery and in favor of Northern interests. 

President Buchanan's administration did little to quell the tension or stop what would become known as "Secession Winter." Between election day and Lincoln's inauguration in March, seven states had seceded from the Union: South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, and Texas. 

In the process, the South took control of federal installations, including forts in the region which would give them a foundation for war. One of the most shocking events occurred when one-quarter of the nation's army surrendered in Texas under the command of General David E. Twigg. Not a single shot was fired in that exchange, but the stage was set for the bloodiest war in American history.