One of Lincoln's earliest and most serious challenges was the secession of Southern states. Before he took office, South Carolina had already seceded, and it was followed by Mississippi, Florida, Alabama, Georgia, Louisiana, Texas, Virginia, Arkansas, North Carolina, and Tennessee in 1861. Lincoln was against expanding slavery, but the American South depended on it to support its largely agrarian economy. When South Carolinians attacked Fort Sumter in April of 1861, the Civil War began. It raged until April of 1865 when General Lee of the Confederacy surrendered to General Grant of the Union.
In 1863, Lincoln signed the Emancipation Proclamation, freeing slaves, but he remained concerned that after the war ended the judiciary could overrule his proclamation. Lincoln wanted a Constitutional amendment to protect it, and it came in December of 1865, months after his death.
Though there were not approval polls for the president's performance like there are now, Lincoln was fairly unpopular by 1863. He faced the challenge of maintaining control of the Union army and building support for his presidency. He was widely regarded as being indecisive; he was said to give his generals too much latitude to make their own strategic decisions. He was forced to revise his leadership style, and in doing so, soon saw victories at Vicksburg and Gettysburg, though casualties reached catastrophic numbers. In his address at Gettysburg, Lincoln not only dedicated the military cemetery but also emphasized the need to finish the was so that the casualties would not have died in vain and that the nation would be reunified.