The central issue in the American Civil War (1861-1865) was slavery. The conflict arose primarily over the moral and economic implications of slavery, particularly its extension into newly acquired territories. The Southern states, reliant on agriculture and slave labor, sought to preserve and expand slavery, while the Northern states increasingly opposed it, viewing it as morally wrong and a barrier to social and economic progress. The election of Abraham Lincoln in 1860, on a platform opposing the expansion of slavery, triggered the secession of several Southern states, leading to a war that ultimately determined the fate of the Union and the future of slavery in the United States.