By condemning slavery's expansion and maintaining that he would not interfere with it where it already existed, Lincoln won the presidential nomination of the Republican party in 1860. Upon his electoral victory, seven states of the lower South seceded and formed the Confederate States of America. At his inauguration in March 1861 Lincoln implored the South to show restraint and tried to dispel its mistrust, but he also pledged to do whatever was necessary to preserve the Union. The South responded by firing on Fort Sumter in Charleston harbor, April 12, 1861. Lincoln, in turn, issued the call for troops to put down the rebellion, and four more states in the Upper South - Virginia, Arkansas, North Carolina, and Tennessee - seceded. The result was four years of bloody conflict. In January 1863 Lincoln issued the Emancipation Proclamation to free slaves within the states in rebellion, thus raising the war to a higher moral plane. In January 1865 he secured Congressional approval of the 13th Amendment that abolished slavery in the United States. In his second Inaugural Address, March 4, 1865, Lincoln offered peace and reconciliation to the South. He was shot by an assassin on April 14, 1865, and died the next day, six days after the surrender of Gen. Robert E. Lee and his troops at Appomattox Court House, Virginia.