In the early script drafts, John was a secondary character. Producer James Middleton explained "Ben-Hur was influenced by Jesus Christ, but it was his story. Much in that way, this [new main] character will be influenced by John Connor." The original ending was to have John killed, and his image kept alive by the resistance by grafting his skin onto Marcus' cybernetic body.
However, after the Internet leak[clarification needed], Warner Bros. decided to completely change the entire third act of the film. McG and Nolan did continue the Christ element of John's character though, in which he has some followers who believe what he knows about Skynet, and others who do not.
McG described the film's theme as "where you draw the line between machines and humans". The friendship between Marcus — who was executed (for murder) when humanity still ruled the world — and Kyle Reese illustrates how war and suffering can bring out the best in people, such as when they worked together to survive during the Blitz. The title was derived from this second chance given to humanity and to Marcus, in addition to John's efforts to save humanity from the machines.