I don't have to wait for a second. For this time period, Abraham Lincoln is far and away the best President. Not only was he self-taught and self-made, he battled manic depression for much of his life. Ultimately, Lincoln asserted once and for all not only federal power but that it is absolutely necessary that every state unite under one banner. It was simply over slavery and Lincoln stood up to the Southern states and did not accept the doctrine of nullification. The doctrine of nullification stems from Thomas Jefferson. While his criticisms came agaisnt a truly embarassing piece of legislation (Alien & Sedition Acts), Jefferson's creation of the doctrine of nullification (states can nullify federal laws) almost destroyed this country and split it in two. The industrial might of the Northern states ultimately played a huge role in the Union's eventual victory, but anyone who has studied the Civil War knows that besides Ulysses S. Grant, the chain of leadership in the Union has absolutely horrendous. Every good American general was from a Confederate state and most had their loyalties there. People genuinely believed that they were first and foremost from their state, then from America. Without Lincoln's leadership from the top, it is very likely that the Union would have lost the war and the powers at be would be the slave powers. Lincoln freed the slaves and reunited the people under the American flag. I can not think of a more critical time in the history of our country and Abraham Lincoln was able to pull us through it. The United States was at a critical breaking point and Lincoln's leadership and guidance saved it. Who knows, half of the people in this country could be living in the Confederate States of America where slavery would have abounded for who knows how many years. He ended the most embarrasing practice that our history has ever acknowledged and saved the country we know.