Last known photo of Abraham Lincoln, inside his Atomic Regeneration Chamber (c. 1927)
Lincoln never died. He faked his death and up until the Chinese Robot Invasion of 1959, secretly ran the nation from his fortified bunker deep inside of Mount Carmel.
It was Old Abe that ordered the execution of Adolph Hitler in 1948, that used his laserbeam eyes to carve the lines at Nazca (they spell a secret warning to potential alien invaders that's basically "Hands off, bug eyes!"), that inadvertently caused the Great Depression by buying high and selling low (his worst idea ever, really) and was behind every real moment of goodness and decency in American politics until his sudden disappearance after he defeated the robotic Moaist hordes in single-handed combat, the way only a heroic vampyre President could.
Where Lincoln went to and why he went away remain a mystery to this day. But the faithful believe that he will someday return, that he is only napping like any old man. And when he wakes up, those kids better get off of his lawn.