Captain Kirk could have lost his own humanity
“The City on the Edge of Forever” remains one of the top episodes of Star Trek: The Original Series and for good reason. Having traveled back in time to the 1930s, Captain Kirk falls in love with Edith Keeler, and he’s devastated to discover she must die or her pacifist movement will allow the Nazis to gain the upper hand. In the end, Kirk is forced to let Edith be hit and killed by a car in order to protect the future of humanity. But that wasn’t the ending that Harlan Ellison had originally written.
According to CBR.com, Ellison had included some strange things in his script that ended up being excluded. Things like a drug deal, a firing squad, and alternate history were given the heave-ho. Though Ellison was infuriated, it wasn’t until the ending of the episode was changed that he asked for his name to be removed from the script.
In Ellison’s script, Kirk didn’t think about the world
According to Ellison, whose quote was included in The Fifty-Year Mission: The Complete, Uncensored, Unauthorized Oral History of Star Trek – The First 25 Years, he was concerned about writing a love story. He wanted to show a love so great that Kirk would sacrifice everything, including his ship, his friends, and even the future itself for this great love.
Ellison’s original script had Kirk seeing the truck coming and realizing he couldn’t let Edith die, no matter what happened to the future. Spock prevents him from going to her, and Edith is still killed. This was the major impact of the script to Ellison—a love that was worth anything and everything, including the loss of humanity.
But Kirk would not have made that type of decision anyway, at least not the captain that had been commanding the Enterprise for an entire season. Duty was ingrained into him. That’s why he and the other members of his crew couldn’t return to the ship when they were infected by the virus in “Miri.” He would not put the ship and the rest of the crew at risk even though they stood a better chance at finding the cure aboard the Enterprise. If he wasn’t willing to infect his crew, he certainly wouldn’t have been willing to sacrifice all of humanity for his own desires.