From April 1861 to April 1865, America was caught in the convulsions of war - The Civil War. No historical event, short of the American Revolution itself, has so deeply affected the United States. The Civil War is often called the war between the states by Southern historians. Thus, even terminology illustrates the political question underpinning the war: was the United States one nation, indivisible under God? Or, were the United States a group of sovereign states, who could choose to disassociate? If America was a union rather than a confederacy of states, then the powerful North could abolish slavery and impose tariffs on the slave-holding, agricultural South. If America was a confederacy, then Southern states could preserve their institutions by peacefully withdrawing from the union.