The American Civil War was a conflict between the United States (the Union or the North) and the eleven states that had seceded from the Union and formed the Confederate States of America (the Confederacy or the South). It lasted from 1861 to 1865. One of the key issues fought over was slavery and the power of the federal government to prohibit it in certain territories. Abraham Lincoln, the first Republican president, promised to keep slavery out of the territories, which was seen as hostile by...