For years, American schoolchildren learned that the question of slavery was the only cause of the Civil War (1861–65): With 19 free states and 15 slave states making up the Union, Abraham Lincoln (1809–1865) had called the country “a house divided” even before he became president. While slavery was central to the conflict, many believe the bloody four-year war had other causes as well.

By the mid-1800s important differences had developed between the South and the North—and many maintain these differences, or vestiges of them, are still with the country today. The economy in the South was based on agriculture while the North was industrialized; the ideals and lifestyles of each region reflected these economic realities. Southerners believed their agrarian lifestyle was dependent on the labor of slaves. For a long time, slavery was viewed by some as a necessary evil. But by the early 1800s the view that slavery is morally wrong was beginning to take hold. Northern abolitionists had begun a movement to end slavery in the states. But, except for a small antislavery faction, these views were not shared in the South.

There were other factors that contributed to the declaration of secession and the formation of the Confederacy, although some still argue these factors were merely smoke screens for the defense of slavery. Disputes between the federal government and the states had limited the power of the states, and this policy was called into question by Southerners. Further, the political party system was in disarray in mid-1850s America. The disorder prompted feelings of distrust for the elected politicians who set national policy. Before the 1860 presidential election, Southern leaders urged that the South secede from the Union if Lincoln, who had publicly taken a stand against slavery, won.