The origins of the American Civil War were rooted in the desire of the Southern states to preserve and expand the institution of slavery. Historians in the 21st century overwhelmingly agree on the centrality of slavery in the conflict, but they disagree on the North's reasons for refusing to allow the Southern states to secede.Aaron Sheehan-Dean, "A Book for Every Perspective: Current Civil War and Reconstruction Textbooks", Civil War History (2005) 51#3 pp. 317–324 The negationist Lost Cause ideology denies that slavery was the principal cause of the secession, a view disproven by historical evidence, including the seceding states' own secession documents. After leaving the Union, Mississippi issued a declaration stating, "Our position is thoroughly identified with the institution of slavery—the greatest material interest of the world."
Background factors in the run up to the Civil War were partisan politics, abolitionism, nullification versus secession, Southern and Northern nationalism, expansionism, economics, and modernization in the antebellum period. As a panel of historians emphasized in 2011, "while slavery and its various and multifaceted discontents were the primary cause of disunion, it was disunion itself that sparked the war."Elizabeth R. Varon, Bruce Levine, Marc Egnal, and Michael Holt at a plenary session of the organization of American Historians, March 17, 2011, reported by David A. Walsh. "Highlights from the 2011 Annual Meeting of the Organization of American Historians in Houston, Texas". HNN online
Abraham Lincoln won the 1860 presidential election as an opponent of the extension of slavery into the U.S. territories. His victory triggered declarations of secession by seven slave states of the Deep South, all of whose riverfront or coastal economies were based on cotton that was cultivated by slave labor. They formed the Confederate States of America after Lincoln was elected in November 1860 but before he took office in March 1861. Nationalists in the North and "Unionists" in the South refused to accept the declarations of secession. No foreign government ever recognized the Confederacy. The refusal of the U.S. government, under President James Buchanan, to relinquish its forts that were in territory claimed by the Confederacy, proved to be a major turning point leading to war. The war itself began on April 12, 1861, when Confederate forces bombarded the Union's Fort Sumter, in the harbor of Charleston, South Carolina.
Slavery
Disagreements between slave states and free states were the main cause of disunion and the war. Most scholars identify preserving slavery as the central reason for the Southern states' decisions to secede."[B]y the dawn of the twenty-first century, a broad consensus regarding Civil War causation clearly reigned. Few mainstream scholars would deny that Abraham Lincoln got it right in his second inaugural address—that slavery was 'somehow' the cause of the war". Woods, Michael E., "What Twenty-First-Century Historians Have Said about the Causes of Disunion: A Civil War Sesquicentennial Review of the Recent Literature", The Journal of American History, Vol. 99, issue 2 (September 2012). The legal institution of human chattel slavery, comprising the enslavement primarily of Africans and African Americans, was prevalent in the United States of America from its founding in 1776 until 1865, predominantly in the South. Under the law, children were born into slavery, and an enslaved person was treated as property that could be bought, sold, or given away. By the time of the American Revolutionary War (1775–1783), enslaved people had been institutionalized as a racial caste associated with African ancestry.
Slavery had been controversial during the framing of the Constitution in 1787, which, because of compromises, ended up with proslavery and antislavery features. The issue had confounded the nation since its inception and increasingly separated the US into a slaveholding South and a free North. The issue was exacerbated by the country's rapid territorial expansion, which repeatedly brought the question of whether new territory should be slaveholding or free. The issue had dominated politics for decades. Attempts to resolve the matter included the Missouri Compromise and Compromise of 1850, but these only postponed the showdown over slavery that would lead to the war. In his second inaugural address in 1865, Lincoln stated:Motivations of supporters on both sides were not uniform; some Northern soldiers were indifferent to slavery, but a pattern emerged. As the war dragged on, more Unionists supported slavery's abolition, either to cripple the Confederacy or on moral grounds. Confederate soldiers fought to protect a Southern society of which slavery was an integral part. Opponents of slavery considered it an anachronistic evil incompatible with republicanism. The strategy of the anti-slavery forces was containment—to stop the expansion of slavery and thereby put it on a path to extinction. The slaveholding interests in the South denounced this as infringing upon their constitutional rights. With large parts of the Southern population in slavery, white Southerners believed the emancipation of slaves would destroy Southern families, society, and the South's economy, with large amounts of capital invested in slaves and longstanding fears of a free black population. Many Southerners feared a repeat of the 1804 Haitian massacre, when former slaves murdered most of Haiti's white population after the successful slave revolution. Historian Thomas Fleming points to the historical phrase "a disease in the public mind" used by critics of this idea and proposes it contributed to the segregation in the Jim Crow era following emancipation. These fears were exacerbated by the 1859 attempt by John Brown to instigate an armed slave rebellion in the South.
Differences in population By the mid-19th century the United States had become a nation of two distinct regions. The free states in New England, the Northeast, and the MidwestThe Mason–Dixon line and the Ohio River were key boundaries. had a rapidly growing economy based on family farms, industry, mining, commerce, and transportation, with a large and rapidly growing urban population. Their growth was fed by a high birth rate and large numbers of European immigrants, especially from Ireland and Germany. The South was dominated by a settled plantation system based on slavery; there was some rapid growth taking place in the Southwest (e.g., Texas), based on high birth rates and high migration from the Southeast; there was also immigration by Europeans, but in much smaller number. The heavily rural South had few cities of any size, and little manufacturing except in border areas such as St. Louis and Baltimore. Slave owners controlled politics and the economy, although about 75% of white Southern families owned no slaves.
Overall, the Northern population was growing much more quickly than the Southern population, which made it increasingly difficult for the South to dominate the national government. By the time of the 1860 election, the heavily agricultural Southern states as a group had fewer Electoral College votes than the rapidly industrializing Northern states. Abraham Lincoln was able to win the 1860 presidential election without even being on the ballot in ten Southern states. Southerners felt a loss of federal concern for Southern pro-slavery political demands, and their continued domination of the federal government was threatened. This political calculus provided a very real basis for Southerners' worry about the relative political decline of their region, due to the North growing much faster in terms of population and industrial output.
Historical tensions and compromises
Early Republic
At the time of the American Revolution, the institution of slavery was firmly established in the American colonies. It was most important in the six southern states from Maryland to Georgia, but the total of a half million slaves were spread out through all of the colonies. In the South, 40 percent of the population was made up of slaves, and as Americans moved into Kentucky and the rest of the southwest, one-sixth of the settlers were slaves. By the end of the Revolutionary War, the New England states provided most of the American ships that were used in the foreign slave trade, while most of their customers were in Georgia and the Carolinas.Fehrenbacher pp. 15–17. Don Fehrenbacher wrote, "As a racial caste system, slavery was the most distinctive element in the southern social order. The slave production of staple crops dominated southern agriculture and eminently suited the development of a national market economy."
No serious national political movement against slavery developed, largely due to the overriding concern over achieving national unity.Fehrenbacher, pp. 16–18 When the Constitutional Convention met, slavery was the one issue "that left the least possibility of compromise, the one that would most pit morality against pragmatism."Goldstone, p. 13 In the end, many would take comfort in the fact that the word "slavery" never occurs in the Constitution. The three-fifths clause was a compromise between those (in the North) who wanted no slaves counted, and those (in the South) who wanted all the slaves counted. The Constitution (Article IV, section 4) also allowed the federal government to suppress domestic violence, a provision that could be used against slave revolts. Congress could not ban the importation of slaves for 20 years. The need for the approval of three-fourths of the states for amendments made the constitutional abolition of slavery virtually impossible.McDougall, p. 318
The importation of slaves into the United States was restricted in 1794, and finally banned in 1808, the earliest date the Constitution permitted (Article 1, section 9). Many Americans believed that the passage of these laws had finally resolved the issue of slavery in the United States.Forbes, p. 4 Any national discussion that might have continued over slavery was drowned out by other issues such as trade embargoes, maritime competition with Great Britain and France, the Barbary Wars, and the War of 1812. A notable exception to this quiet regarding slavery was the New Englanders' association of their frustration with the war with their resentment of the three-fifths clause that seemed to allow the South to dominate national politics.Mason, pp. 3–4
During the aftermath of the American Revolution (1775–1783), the Northern states (north of the Mason–Dixon line separating Maryland from Pennsylvania and Delaware) abolished slavery by 1804, although in some states older slaves were turned into indentured servants who could not be bought or sold. In the Northwest Ordinance of 1787, Congress (at that time under the Articles of Confederation) barred slavery from the Midwestern territory north of the Ohio River.Paul Finkelman, "Slavery and the Northwest Ordinance: A Study in Ambiguity", Journal of the Early Republic 6.4 (1986): 343–370. When Congress organized the territories acquired through the Louisiana Purchase of 1803, there was no ban on slavery.John Craig Hammond, "'They Are Very Much Interested in Obtaining an Unlimited Slavery': Rethinking the Expansion of Slavery in the Louisiana Purchase Territories, 1803–1805", Journal of the Early Republic 23.3 (2003): 353–380.
Missouri Compromise