Elder, Bill, and John Severin. "…For Us the Living"
Divergence: 1865 CE
What if: Abraham Lincoln wasn't assassinated and lived to start a political movement which created a worldwide Utopia.
Summary: A physicist arrested by the FBI in 1953 claims to be from this other world, to have invented a time machine and to have caused Lincoln's death.
Published: In Weird Fantasy #20 (July/August 1953, Educational Comics); Weird Fantasy #20 (July 1997, Gemstone).