Each state declared its secession from the United States following the November 1860 election of Republican candidate Abraham Lincoln to the U.S. presidency on a platform which opposed the expansion of slavery into the western territories. Before Lincoln took office in March, a new Confederate government was established in February 1861, which was considered illegal by the government of the United States. States volunteered militia units and the new government hastened to form its own Confederate States Army from scratch practically overnight. After the American Civil War began in April, four slave states of the Upper South—Virginia, Arkansas, Tennessee, and North Carolina—also declared their secession and joined the Confederacy. The Confederacy later accepted Missouri and Kentucky as members, although neither officially declared secession nor were they ever largely controlled by Confederate forces; Confederate shadow governments attempted to control the two states but were later exiled from them.
The government of the United States (the Union) rejected the claims of secession and considered the Confederacy illegitimate. The War began with the Confederate attack upon Fort Sumter on April 12, 1861, a Union fort in the harbor of Charleston, South Carolina. No foreign government officially recognized the Confederacy as an independent country, although Great Britain and France granted it belligerent status, which allowed Confederate agents to contract with private concerns for arms and other supplies. In early 1865, after four years of heavy fighting which led to over 650,000-1,000,000+ military deaths, all the Confederate forces surrendered and the Confederacy vanished. The war lacked a formal end; nearly all Confederate forces had been forced into surrender or deliberately disbanded by the end of 1865, by which point the dwindling manpower and resources of the Confederacy were facing overwhelming odds. By 1865, Jefferson Davis lamented that the Confederacy had "disappeared".
On February 22, 1862, the Confederate Constitution of seven state signatories – Mississippi, South Carolina, Florida, Alabama, Georgia, Louisiana, and Texas – replaced the Provisional Constitution of February 8, 1861, with one stating in its preamble a desire for a "permanent federal government". Four additional slave-holding states – Virginia, Arkansas, Tennessee, and North Carolina – declared their secession and joined the Confederacy following a call by U.S. President Abraham Lincoln for troops from each state to recapture Sumter and other seized federal properties in the South. Missouri and Kentucky were represented by partisan factions from those states, while the legitimate governments of those two states retained formal adherence to the Union. Also fighting for the Confederacy were two of the "Five Civilized Tribes" – the Choctaw and the Chickasaw – in Indian Territory and a new, but uncontrolled, Confederate Territory of Arizona. Efforts by certain factions in Maryland to secede were halted by federal imposition of martial law; Delaware, though of divided loyalty, did not attempt it. A Unionist government in western parts of Virginia organized the new state of West Virginia, which was admitted to the Union during the war on June 20, 1863.
Confederate control over its claimed territory and population in congressional districts steadily shrank from 73% to 34% during the course of the American Civil War due to the Union's successful overland campaigns, its control of the inland waterways into the South, and its blockade of the southern coast. With the Emancipation Proclamation on January 1, 1863, the Union made abolition of slavery a war goal (in addition to reunion). As Union forces moved southward, large numbers of plantation slaves were freed. Many joined the Union lines, enrolling in service as soldiers, teamsters and laborers. The most notable advance was Sherman's "March to the Sea" in late 1864. Much of the Confederacy's infrastructure was destroyed, including telegraphs, railroads and bridges. Plantations in the path of Sherman's forces were severely damaged. Internal movement became increasingly difficult for Southerners, weakening the economy and limiting army mobility.
These losses created an insurmountable disadvantage in men, materiel, and finance. Public support for Confederate President Jefferson Davis's administration eroded over time due to repeated military reverses, economic hardships, and allegations of autocratic government. After four years of campaigning, Richmond was captured by Union forces in April 1865. A few days later General Lee surrendered to Union General Ulysses S. Grant, effectively signalling the collapse of the Confederacy. President Davis was captured on May 10, 1865, and jailed in preparation for a treason trial that was ultimately never held.
The initial Confederacy was established in the Montgomery Convention in February 1861 by 7 states (SC, MS, AL, FL, GA, LA, adding TX in March before Lincoln's inauguration), expanded in May–July 1861 (with VA, AR, TN, NC), and was disintegrated in April–May 1865. It was formed by delegations from seven slave states of the Lower South that had proclaimed their secession from the Union. After the fighting began in April, four additional slave states seceded and were admitted. Later, two slave states (Missouri and Kentucky) and two territories were given seats in the Confederate Congress. Southern California, although having some pro-Confederate sentiment, was never organized as a territory.
Many southern whites had considered themselves more Southern than American and were prepared to fight for their state and their region to be independent of the larger nation. That regionalism became a Southern nationalism, or the "Cause". For the duration of its existence, the Confederacy underwent trial by war. The "Southern Cause" transcended the ideology of states' rights, tariff policy, or internal improvements. This "Cause" supported, or descended from, cultural and financial dependence on the South's slavery-based economy. The convergence of race and slavery, politics, and economics raised almost all South-related policy questions to the status of moral questions over way of life, commingling love of things Southern and hatred of things Yankee (the North). Not only did national political parties split, but national churches and interstate families as well divided along sectional lines as the war approached. According to historian John M. Coski,