Richard Shenkman is the author of Presidential Ambition: How the Presidents Gained Power, Kept Power and Got Things Done. He was interviewed by CSPAN about Abraham Lincoln's own ambitions:
Abraham Lincoln is the one president who was probably the most ambitious. With all the stereotypes about Abraham Lincoln -- country lawyer, Honest Abe, stovepipe hat, all of this kind of stuff --you never hear the word "ambitious" come into the picture, but he was ambitious. His law partner, William Herndon said, "His ambition was an engine that knew no rest."
Just take this little mental picture -- when Lincoln was twenty-three years old, he moved into New Salem, Illinois. He knew nobody, had no money, no power, no connections. He was a poor farm boy. He was a poor farm hand who was earning a living by plowing other people's fields. He didn't have his own farm; he didn't have enough money to rent a real home. He rented out the back bedrooms of different people, and he lived two weeks here, a couple of months there. Six months after moving into New Salem -- with one year total education in his entire life -- he announced in the local paper that he was running for a seat in the state legislature. That's ambition. He lost, but he ran again two years later and won. He kept running his whole life, and he could never run fast enough. No matter how quickly he climbed the pole, he always thought it wasn't quick enough. He always wanted to get ahead. This is why he was one of the youngest presidents we ever had.
The first twenty U.S. presidents never lied about their health, and yet, they had bad health all the time. George Washington, a year after taking office, got pneumonia and nearly died from it. Thomas Jefferson, during his first term, had constant diarrhea. He was always sick. It's one of the reasons why he was always going back to Monticello, because his physician said, "If you do a lot of horseback riding, there's going to be a solution." Who knows? That was not much of a cure. Jackson had abscesses constantly in his arm and in his lungs from bullet wounds. He'd been in a bar brawl and taken a shot. He was coughing up blood constantly. He could never get through a whole eight hours of sleep at night. He had terrible health problems. The, of course, you come to Abe Lincoln, [who had] melancholia. He really was the first president who probably should have had Prozac. He was depressed all the time.
[Except for George Washington], all the other presidents tended to fudge an awful lot [in times of war]. They played politics with war, even Abraham Lincoln . . . Lincoln was determined to win the Civil War, but he was even more determined, in a way, to win re-election in 1864. He knew that U.S. Grant was the best general in the army; he knew that after the great victory at Vicksburg in Mississippi. But Lincoln [initially] declined to bring Grant east to take over as commander in chief of the Army of the Potomac because he was afraid that Grant, from that position, would then run for president against him. After he got word back -- and several months had elapsed -- then he finally appointed Grant. He played politics with national security in the middle of the Civil War when tens of thousands of peoples' lives were lost. That's what presidents do. Even Abe Lincoln.