The American civil war started in 1861 and ended in 1865. The theme of the war was whether the enslavement of black people in the southern states should continue. Northern victory in the war allowed United States as one nation and stopped the institution of slavery. The American Civil War was the most destructive conflict in the Western world that led to the death of 625,000 lives. Abraham Lincoln being the then president of America played a crucial role in the war.