The American Civil War (1861–1865) stands as the central event in the historical consciousness of the United States. While the American Revolution (1776–1783) created the nation, it was the Civil War that determined what kind of country it would become. Two fundamental questions remained unresolved after the revolution: Would the United States be a dissolvable confederation of sovereign states or an indivisible nation with a sovereign national government? And how would the institution of slavery persist in a nation founded on the principle that all men were created equal and entitled to liberty?
The North’s victory in the war preserved the United States as one nation and ended the institution of slavery that had divided the country since its founding. However, these achievements came at the cost of 625,000 lives—nearly as many American soldiers as died in all the other wars fought by the United States combined. The Civil War was the largest and most destructive conflict in the Western world between the end of the Napoleonic Wars in 1815 and the onset of World War I in 1914.
The conflict began due to uncompromising differences between free and slave states over the power of the national government to prohibit slavery in territories that had not yet become states. When Abraham Lincoln was elected in 1860 as the first Republican president on a platform pledging to keep slavery out of those territories, seven deep South slave states seceded and formed a new nation: the Confederate States of America. The incoming Lincoln administration and most Northern citizens refused to recognize the legitimacy of secession, fearing it would discredit democracy and create a fatal precedent that could eventually fragment the United States into several small, squabbling countries.
The spark that ignited the war occurred on April 12, 1861, when Confederate forces attacked Fort Sumter in South Carolina. In the years that followed, bloody battles scarred the American landscape, from Gettysburg in Pennsylvania to Vicksburg on the Mississippi River. By 1864, the initial goal of limited war to restore the Union had evolved into a strategy of “total war,” aimed at destroying the Old South and its economic and social foundations, including slavery.
Finally, in April 1865, Robert E. Lee, commander of the Army of Northern Virginia, surrendered to Ulysses S. Grant at Appomattox. With the capture of Confederate President Jefferson Davis in May of that year, resistance collapsed, and the war came to an end. The long and painful process of rebuilding a united nation free of slavery had begun.