Long a supporter of abolition, he ran for President as a member of the idealistic, young Rebublican Party. He was elected due to his more politically popular opponants splitting the vote, only to have half of his Nation rise up in war. He spent his whole time as President with this struggle, enduring untold amounts of personal attacks from within his own side, while dealing with the Southern secession and war.
During this he experienced the loss of a beloved son, a succession of incompetant field commanders early on, enormous pressure from Europe to lift the blockade, and riots in the North. Add the unprecedented carnage that was introduced by a combo of outdated tactics and modern weapons.
Yet, he persevered in his duty. Then when, victorious at last, he could set his hand to peace and healing, he was murdered in front of his wife by a coward casting himself as a patriot.
The stuff of Epic Tragedy, the flawed Hero to weep for. Shakespeare could have written it.