History: American Civil War (1861-1865)

The American Civil War was one of the earliest true industrial wars. Railroads, the telegraph, steamships, and mass-produced weapons were employed extensively. The practices of total war, developed by Sherman in Georgia, and of trench warfare around Petersburg foreshadowed World War I in Europe. It remains the deadliest war in American history, resulting in the deaths of 620,000 soldiers and an undetermined number of civilian casualties. Ten percent of all Northern males 20–45 years of age died, as did 30 percent of all Southern white males aged 18–40. Victory for the North meant the end of the Confederacy and of slavery in the United States, and strengthened the role of the federal government. The social, political, economic and racial issues of the war decisively shaped the reconstruction era that lasted to 1877.
Causes of secession
The Abolitionist movement in the United States had roots in the Declaration of Independence. Slavery was banned in the Northwest Territory with the Northwest Ordinance of 1787. By 1804 all the Northern states had passed laws to abolish slavery. Congress banned the African slave-trade in 1808, although slavery grew in new states in the deep south. The Union was divided along the Mason Dixon Line into the North (free of slaves), and the South, where slavery remained legal.