Seems like Lincoln is everyone's favorite president and superhero. Andy Duncan's too. So we have Lincoln in Frogmore, a World Fantasy Award nominee in 2001.
This story is really all about the setting--Sea Island Georgia, during the Civil War. The setup is a WPA writer's project interview of a man who was a young boy at the time. And supposedly Abraham Lincoln snuck into Frogmore to give the "coloreds" there a speech. All in Sea Island vernacular, one supposes because that is the tale teller's voice. I can't pass judgement on Duncan's authenticity, it seems all well enough. But the story really doesn't do anything more than show that he can write that way. Lincoln in reality is not convincing as a hidden true friend of slaves, down home as he was. The premise ends up more odd than speculative. I give it 2 stars, not really worth going out of your way for, though it is OK.