Abraham Lincoln was elected president on a purely sectional vote, and as he prepared to begin his presidency, he was faced with the possibility, even probability, of disunion, as many people in the South renounced his election. The issues at the top of the list were states' rights, the expansion (or not) of slavery into US territories, and the Northern lack of enforcement of the Fugitive Slave Act.
Before Lincoln even took office on March 4, 1861, seven Southern states had already seceded from the Union, and the new president had to decide what to do about it. On April 15, he chose to call for 75,000 troops, an action that nudged four more states out of the Union. After the debacle at Fort Sumter, Abraham Lincoln ended up with a civil war on his hands.
Lincoln's primary task for the next four years was to manage a war, both militarily and politically. He had to cope with everything from incompetent generals to opposition in the North. He had to decide what to do about slavery and when to do it, and he finally issued the Emancipation Proclamation on January 1, 1863.
In 1864, Lincoln faced a campaign for reelection against George McClellan. He won, but only after a time in which his victory was in serious doubt. At the beginning of Lincoln's second term, the war was starting to draw to a close, and Lincoln needed to plan for the renewal of the Union and the reconstruction of the South. Again, he faced serious opposition here. Indeed, Lincoln's presidency was far from easy, and his problems only multiplied as the years passed.