Origins of The American Civil War

Historians debating the origins of the American Civil War focus on the reasons seven states declared their secession from the U.S. and joined to form the Confederate States of America (the "Confederacy"). The main explanation is slavery, especially Southern anger at the attempts by Northern antislavery political forces to block the expansion of slavery into the western territories. Southern slave owners held that such a restriction on slavery would violate the principle of states' rights.

Abraham Lincoln won the 1860 presidential election without being on the ballot in ten of the Southern states. His victory triggered declarations of secession by seven slave states of the Deep South, and their formation of the Confederate States of America, even before Lincoln took office. Nationalists (in the North and elsewhere) refused to recognize the secessions, nor did any foreign government, and the U.S. government in Washington refused to abandon its forts that were in territory claimed by the Confederacy. War began in April 1861 when Confederates attacked Fort Sumter, a major U.S. fortress in South Carolina, the state that had been the first to declare its independence.

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." States' rights and the tariff issue became entangled in the slavery issue, and were intensified by it. Other important factors were party politics, abolitionism, Southern nationalism, Northern nationalism, expansionism, sectionalism, economics and modernization in the Antebellum period.

The United States had become a nation of two distinct regions. The free states in New England, the Northeast, and the Midwest 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 Irish, British and German. 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, but it had a much lower immigration rate from Europe. The South also had fewer large cities, and little manufacturing except in border areas. Slave owners controlled politics and economics, though about 70% of Southern whites owned no slaves and usually were engaged in subsistence agriculture.

Overall, the Northern population was growing much more quickly than the Southern population, which made it increasingly difficult for the South to continue to influence 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. 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 continued domination of the Federal government by "Slaveocracy" was on the wane. 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.

In the interest of maintaining unity, politicians had mostly moderated opposition to slavery, resulting in numerous compromises such as the Missouri Compromise of 1820. After the Mexican-American War, the issue of slavery in the new territories led to the Compromise of 1850. While the compromise averted an immediate political crisis, it did not permanently resolve the issue of the Slave power (the power of slaveholders to control the national government on the slavery issue). Part of the 1850 compromise was the Fugitive Slave Law of 1850, requiring that Northerners assist Southerners in reclaiming fugitive slaves, which many Northerners found to be extremely offensive.

Amid the emergence of increasingly virulent and hostile sectional ideologies in national politics, the collapse of the old Second Party System in the 1850s hampered efforts of the politicians to reach yet one more compromise. The compromise that was reached (the 1854 Kansas-Nebraska Act) outraged too many northerners, and led to the formation of the Republican Party, the first major party with no appeal in the South. The industrializing North and agrarian Midwest became committed to the economic ethos of free-labor industrial capitalism.

Arguments that slavery was undesirable for the nation had long existed, and early in U.S. history were made even by some prominent Southerners. After 1840, abolitionists denounced slavery as not only a social evil but a moral wrong. Many Northerners, especially leaders of the new Republican Party, considered slavery a great national evil and believed that a small number of Southern owners of large plantations controlled the national government with the goal of spreading that evil. Southern defenders of slavery, for their part, increasingly came to contend that blacks actually benefited from slavery, an assertion that alienated Northerners even further.