The Terminator series seems easy to sum up: An evil artificial intelligence from the future (Skynet) keeps sending killer robots to the past to kill the future leader of the human resistance (John Connor), but fails. It's pretty straight forward until you start thinking about it, then it falls apart.
Why not kill John Connor when he's five, instead of 13? Why not kill his mother when she's a little girl? Why not send more than one robot back at a time? Or go back further and kill her parents? And so on and so forth. As I was wrestling with these questions (as I tend to do) it hit me:
Skynet isn't trying to kill John Connor. Skynet is trying to weaken the human resistance by changing who John Connor is.
Let's take this thing piece by piece. First up, Skynet.
Skynet was the world's first and last man-made intelligence created to assist in military operations and generally keep everyone safe. As happens with artificial intelligence, it became self aware and opted to wipe out the human race (you know, like you do). We can surmise that as a super intelligent computer, Skynet can comprehend things that the human mind can barely wrap it's thoughts around, like the Fourth Dimension.
If we can believe that Skynet can create a time platform (which it did), then we we have to believe that it knows the consequences of it's actions. It knows that to change too much in the past would be to alter the future in unforeseen ways, possibly in ways that Skynet doesn't exist. Couple this with the John Connor led human resistance turning the tide in the war, and Skynet's motive becomes clear.
Let's move on to John Connor. When we first meet him in The Terminator, John is a capable, cunning, strategic genius leading the human resistance to victory. For clarity sake I'm going to call this John Conner, AlphaJohn as he's our model of what John should be.
AlphaJohn was raised in Los Angeles, CA by a single mother who taught him how to work hard to get what he wanted. She instilled in him the strength that he now uses to lead the resistance. While his life wasn't perfect, his experiences shaped him to be the great leader that he is. So when it came time to save his mother from time-travelling robots, he didn't hesitate to send his best solider to save her and Kyle Reese was proud to go on the mission.
And so, AlphaJohn walked right into Skynet's trap.
The first Terminator movie follows Sarah Connor as she escapes these killer robots with the help of Kyle Reese. Throughout the film, the two are drawn closer and totally bang out without protection (as people tend to do when they share a traumatic experience). And as you would expect, Sarah gets pregnant.
It's here that the first major divergence is made: Kyle Reese is now John's father. This John, OmegaJohn, will be born into a world where his mother knows the 'future' and will put into his head at a young age that he is to be the savior of humanity. It's time for the next phase of Skynet's plan.
Terminator 2 starts with John Connor leading the human resistance, this time just a strong thorn in Skynet's side instead of having it on the ropes. This John, BetaJohn, learns of a time-travelling assassination plot and opts to send his own Terminator back in time to stop it and save himself. Already this John is different than his predecessor, being more comfortable with machines than people and unable to scrounge up a volunteer for the mission.
The T-1000, Skynet's assassin, arrives in the past with the with the orders to find Sarah Connor and use her as bait for John. And so, the second phase of Skynet's plan starts to fall into place.
OmegaJohn at this point has a fairly stable family life. Sure he's the son of a crazy woman currently in a mental hospital, but his foster family offer him the strong familial presence that will guide him to being a pretty good leader. When the movie begins, he's in the midst of his teenage rebellious phase, a crucial point in his development.
While ultimately the T-1000 fails to kill OmegaJohn or Sarah, he succeeds in bringing the two together and eliminating OmegaJohn's foster family. Sarah, now more than ever sure about the future, will push OmegaJohn to be a better solider and reenforce his messiah complex, but will neglect to foster the experiences that really shape him into a hero.
Skynet's plan is almost complete.
Skynet has already partially succeeded when Terminator 3 begins; John Connor (GammaJohn, if you're keeping track) has been killed. Unfortunately for Skynet, the resistance is propelled forward by GammaJohn's loving wife Kate. As a result, Skynet sends another assassin, the T-X, back in time to eliminate Kate, or so it seems. Meanwhile Kate pulls her best GammaJohn impression and sends back her own robot protector, The T-850, to keep her and John safe in the past.
When we meet OmegaJohn in Terminator 3 he's a lonely drifter, paranoid and living off the grid. His mother's teachings about how the machines would rise up have alter John almost completely leaving him a shell of the man he would be. Given time, he'd figure out how to be that man (mostly) meet Kate and ultimately marry her, Skynet hopes to speed the process along.
For all the help it brings, the T-850 does more harm than good. In order to protect the both Kate and OmegaJohn, the robot brings the two of them together before they were supposed to meet AND reveals their future together. OmegaJohn ought to be used to this by now, but surely Kate was not and seems to resent OmegaJohn throughout most of the movie.
In the end the T-X doesn't kill Kate or OmegaJohn, but does succeed in hindering their relationship. As the film ends, our destined lovers find themselves trapped in a bomb shelter, alone, as they ride out Judgement Day.
Something tells me that Kate is a woman who likes to make up her own mind and doesn't like to be told who she's going to marry without having a say. That nugget of resentment will fester, and ultimately hinder her in the future.
Finally Skynet's plan is complete. We're left with a completely ineffectual John Connor, and now is the time eliminate the humans for good.
Enter Terminator: Salvation, the fruits of Skynet's labors. Here OmegaJohn is a half-crazed, reckless solider with a messiah complex desperately trying to get the resistance to listen to him. HIs life experiences, instead of making him the capable leader have made him a lunatic that few truly believe in.
Ultimately, in this future, Skynet will succeed in destroying the human race and won't have to resort to using time-travelling robots to do so.
That's how Skynet pulled off the greatest long con in all of fiction.