Secession, the withdrawal of part of a country or state from the central government's control. The withdrawal may be carried out peacefully or violently. Political conflicts that lead to secession are usually based on economic, cultural, or religious differences.

In United States history the question of secession arose several times before the Civil War, but the term generally refers to the withdrawal of the Southern states from the Union in 1860–61. Secession has also been an issue in other countries. Panama in 1903 seceded from Colombia partly because of Colombian opposition to plans by the United States to construct the Panama Canal. In 1967 the Ibo tribe of Nigeria, unwilling to be ruled by other tribes of that African country, tried to set up the Eastern Region as the separate nation of Biafra. Some French Canadians urge that the Province of Quebec secede from Canada on the grounds of political and cultural discrimination.

In the United States

From the time the U.S. Constitution was adopted, supporters of the doctrine of states' rights regarded secession as a right belonging to the states under the 10th Amendment The Kentucky and Virginia Resolutions of 1798, though they did not use the word secession, stressed the sovereignty of the individual states.

In 1803–04 a small number of New England Federalists, facing decreased political power as a result of the admission of Southern states to the Union, proposed a separate nation to be called the Northeastern Confederacy. The idea did not gain support and was abandoned. Other Federalists hinted at secession in the Hartford Convention, 1814–15, called to protest the War of 1812, but they were disregarded. In 1832 South Carolina raised the threat of secession in the nullification crisis. (

To many Southerners the election to the Presidency in 1860 of Abraham Lincoln, who won with exclusively Northern support, placed in jeopardy both slavery and states' rights. Southerners knew that abolition of slavery, the basis of the cotton economy, would be financially disastrous. Even if slavery were retained, the South feared political domination by the North, which was attempting to bar extension of slavery into all future new states.

Although there were groups in each state that were strongly opposed to secession, in 1860–61 seven states in what was known as the Lower South seceded. On February 4, 1861, they formed the Confederate States of America. After Lincoln's call in April for a militia to enforce federal authority, four border, or Upper South, states seceded and joined the Confederacy. (In one of these states, Virginia, the western counties refused to secede from the Union. They set up their own government and in 1863 became the state of West Virginia.)

Lincoln rejected the argument put forth in the Confederacy that secession was constitutional and treated the secessionist states as groups in rebellion. The South's attempt to secede was thwarted by force of arms, and the constitutionality of secession has never been determined.