Superman didn't save John F. Kennedy when the U.S. President was assassinated in Dallas, as the president sent him on a different mission.
Warning! Spoilers for Superman & The Authority by DC Comics below.
DC Comics has revealed Superman offered to protect John F. Kennedy before his assassination in Dallas, but the former President of the United States declined his offer - saying he needed the hero somewhere else entirely. In Superman and the Authority #1, JFK says he has bigger plans for Superman as he wants him to help end war and take the country to space. Unfortunately, in doing so, Superman can't save the President.
In Superman and the Authority by Grant Morrison, Mikel Janin, Jordie Bellaire, and Steve Wands, readers are immediately taken back to 1963, where Kal-El meets with President Kennedy at the White House. Kennedy tells Superman he's exactly what America needs at the moment and that he can inspire the country during the turbulent period. Recounting the days of the Justice Society and the Mystery Men and their efforts to make a difference during War and unjust times, Kennedy says he wants Superman and heroes like him to stand tall, help end war, and take the U.S. to the stars.
The conversation between Kennedy and Superman is full of hope, as the President of the United States counts on Superman to make a difference and make the world a finer place. Kal-El gives Kennedy his word he will help make a better world for everyone. However, after a warm chat between the two, the comic flashes to Kennedy getting assassinated in Dallas. The terrifying scene is juxtaposed with Superman assisting astronauts on the Moon, revealing Superman could not save JFK because he was in space.
Later in the comic, an older version of Superman captures Manchester Black and repeats he always wanted to make the world a better place. He says he made a promise to JFK, but after his assassination, everything started to crumble. He mentions the murders of Bobby Kennedy and Martin Luther King, the space race, plus villains such as the Intergang, Darkseid, and Doomsday as changing the path of peace. Superman admits to Manchester Black that he and the Justice League have run out of time to deliver on the promise to JFK of a better world. Ultimately, Superman reveals to Manchester Black his powers are failing, and he needs a team to reach beyond law and consensus.
Superman's seen a lot of darkness in his lifetime, including not being there for JFK (even if the President did instruct him to not serve as protection) and he's keen on making sure his promise is fulfilled - even decades later. Teaming up with Manchester Black might seem odd, but Superman sees it as a path to the peaceful world both he and the former President always envisioned. Superman and The Authority #1 is in comic book stores now.
