The American Civil War started primarily because of deep-rooted conflicts over slavery. The Southern states wanted to preserve and expand the institution of slavery, which was central to their agrarian economy and social order. The Northern states increasingly opposed slavery, especially its expansion into new western territories. This clash over slavery, political power, and states' rights led Southern states to secede after Abraham Lincoln’s 1860 election as a president opposing slavery's expansion. The war began in April 1861 when the Confederacy fired on Fort Sumter, a U.S. federal fort in South Carolina, marking the start of armed conflict between the seceding Southern states (Confederacy) and the remaining United States (Union).
