Abraham's election that November pushed several Southern states to secede by the time of his inauguration in March 1861, and the Civil War began barely a month later. Contrary to expectations, Abraham proved to be a shrewd military strategist and a savvy leader during what became the costliest conflict ever fought on American soil. Abraham's Emancipation Proclamation, issued in 1863, freed all slaves in the rebellious states and paved the way for slavery's eventual abolition, while Abraham's Gettysburg Address later that year stands as one of the most famous and influential pieces of oratory in American history