Secession of South Carolina

South Carolina did more to advance nullification and secession than any other Southern state. South Carolina adopted the "Declaration of the Immediate Causes Which Induce and Justify the Secession of South Carolina from the Federal Union" on December 24, 1860. It argued for states' rights for slave owners in the South, but contained a complaint about states' rights in the North in the form of opposition to the Fugitive Slave Act, claiming that Northern states were not fulfilling their federal obligations under the Constitution. All the alleged violations of the rights of Southern states were related to slavery.

Secession winter

Before Lincoln took office, seven states had declared their secession from the Union. They established a Southern government, the Confederate States of America on February 4, 1861. They took control of federal forts and other properties within their boundaries with little resistance from outgoing President James Buchanan, whose term ended on March 4, 1861. Buchanan said that the Dred Scott decision was proof that the South had no reason for secession, and that the Union "was intended to be perpetual", but that "the power by force of arms to compel a State to remain in the Union" was not among the "enumerated powers granted to Congress". One quarter of the U.S. Army—the entire garrison in Texas—was surrendered in February 1861 to state forces by its commanding general, David E. Twiggs, who then joined the Confederacy.

As Southerners resigned their seats in the Senate and the House, Republicans were able to pass bills for projects that had been blocked by Southern Senators before the war, including the Morrill Tariff, land grant colleges (the Morill Act), a Homestead Act, a trans-continental railroad (the Pacific Railway Acts), the National Banking Act and the authorization of United States Notes by the Legal Tender Act of 1862. The Revenue Act of 1861 introduced the income tax to help finance the war.

The Confederacy

Seven Deep South cotton states seceded by February 1861, starting with South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, and Texas. These seven states formed the Confederate States of America (February 4, 1861), with Jefferson Davis as president, and a governmental structure closely modeled on the U.S. Constitution.

Following the attack on Fort Sumter, President Lincoln called for a volunteer army from each state. Within two months, four more Southern slave states declared their secession and joined the Confederacy: Virginia, Arkansas, North Carolina and Tennessee. The northwestern portion of Virginia subsequently seceded from Virginia, joining the Union as the new state of West Virginia on June 20, 1863. By the end of 1861, Missouri and Kentucky were effectively under Union control, with Confederate state governments in exile.

The Union states

Twenty-three states remained loyal to the Union: California, Connecticut, Delaware, Illinois, Indiana, Iowa, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, New Hampshire, New Jersey, New York, Ohio, Oregon, Pennsylvania, Rhode Island, Vermont, and Wisconsin. During the war, Nevada and West Virginia joined as new states of the Union. Tennessee and Louisiana were returned to Union military control early in the war.

The territories of Colorado, Dakota, Nebraska, Nevada, New Mexico, Utah, and Washington fought on the Union side. Several slave-holding Native American tribes supported the Confederacy, giving the Indian Territory (now Oklahoma) a small, bloody civil war.

Border states

The border states in the Union were West Virginia (which separated from Virginia and became a new state), and four of the five northernmost slave states (Maryland, Delaware, Missouri, and Kentucky).

Maryland had numerous pro-Confederate officials who tolerated anti-Union rioting in Baltimore and the burning of bridges. Lincoln responded with martial law and sent in militia units from the North. Before the Confederate government realized what was happening, Lincoln had seized firm control of Maryland and the District of Columbia, by arresting all the prominent secessionists and holding them without trial (they were later released).

In Missouri, an elected convention on secession voted decisively to remain within the Union. When pro-Confederate Governor Claiborne F. Jackson called out the state militia, it was attacked by federal forces under General Nathaniel Lyon, who chased the governor and the rest of the State Guard to the southwestern corner of the state. (See also: Missouri secession). In the resulting vacuum, the convention on secession reconvened and took power as the Unionist provisional government of Missouri.

Kentucky did not secede; for a time, it declared itself neutral. When Confederate forces entered the state in September 1861, neutrality ended and the state reaffirmed its Union status, while trying to maintain slavery. During a brief invasion by Confederate forces, Confederate sympathizers organized a secession convention, inaugurated a governor, and gained recognition from the Confederacy. The rebel government soon went into exile and never controlled Kentucky.

After Virginia's secession, a Unionist government in Wheeling asked 48 counties to vote on an ordinance to create a new state on October 24, 1861. A voter turnout of 34% approved the statehood bill (96% approving). The inclusion of 24 secessionist counties in the state and the ensuing guerrilla war engaged about 40,000 Federal troops for much of the war. Congress admitted West Virginia to the Union on June 20, 1863. West Virginia provided about 22-25,000 Union soldiers, and at least 16,000 Confederate soldiers.

A Unionist secession attempt occurred in East Tennessee, but was suppressed by the Confederacy, which arrested over 3000 men suspected of being loyal to the Union. They were held without trial.