American Civil War

The American Civil War (1861–1865) was a bitter sectional conflict that began after southern states of the United States declared their secession from the Union and formed the Confederate States of America. The United States did not recognize any right of secession, and fighting began after the Confederacy used force to seize U.S. federal property within its boundaries. After a fairly quiet first year, three very bloody years of fighting ended with a decisive Union victory, followed by a period of Reconstruction. The war produced more than 970,000 casualties (3 percent of the population), including approximately 620,000 deaths. The causes of the war, the reasons for the outcome, and even the name of the war itself, are subjects of much controversy, even today.

Causes
The origins of the American Civil War lay in the complex issues of slavery, politics, disagreements over the scope of States' rights, Manifest Destiny, sectionalism, economic competition, modernization, and competing nationalisms of the Antebellum period. Although there is little disagreement among historians on the details of the events that led to war, there is much controversy on exactly what caused what and the relative importance. There is no consensus on whether the war could or should have been avoided.