Last episode on Steins;Gate, Okabe finally broke the 1% barrier and returned to the original timeline at the cost of his companion’s life. Now John Titor has come back to tell him that his work is not done, that World War 3 is going to break out if he doesn’t do something. This seems like a perfect opportunity for him to enter a third timeline and save Makise Kurisu’s life. I won’t even complain about the writers undoing a poignant death for the sake of a happy ending – in a time travel show, that’s perfectly fair. In fact that’s what you should be doing with time travel! Undo everyone’s poignant deaths and create for us a happy ending, Okabe! Or at least get a start on it, I don’t think episode 23 of Steins;Gate is the last episode of Steins;Gate.
…thirty minutes pass…

I realize you're just trying to show how much you care about Makise Kurisu, Okabe, but that's an incredibly awful thing to say. Imagine telling a guy you don't care that his whole family died, and then multiply that a billionfold.
I was a little confused as to why they had Okabe playing bodyguard for Makise Kurisu instead of John Titor who has actually had some combat training and knows the mission, but then it all became clear. Gosh, future Okabe’s kind of a dick. You would figure if you could trust anybody not to send you on a wild goose chase and make you murder the woman you love it would be yourself. On the other hand, you are probably the only person who would forgive yourself for an asshole move like that, if you understood it was necessary. Okabe wouldn’t doubt his own motives… except to the extent that 15 years and the eruption of world war 3 might change his value set. But he knows himself well enough to know that all he has to do is dangle the prospect of saving Makise Kurisu in front of him and he’ll do whatever he says.
It’s a little strange to think that the key to changing the timeline is to preserve the original Okabe’s observations. That doesn’t seem to fit with time travel physics as we know it… except for one thing. We know Okabe is special – he has the power of Reading Steiner. His Reading Steiner activates when the timeline shifts, and he experiences disorientation as his memories fail to line up with his past experiences. This could be his brainwaves syncing, as with the Time Leap machine. We know there is some disorientation involved in using that. But in that case, how is it possible to get the Reading Steiner to activate across gaps of ten years, as in the case of the crossdresser? With the Time Leap machine, we know that only leaps of up to two days are possible, because beyond that the world is too different and you can’t sync. Is Okabe’s brain just that much more adaptable? But we’ve seen him Time Leap, he doesn’t go back further than two days and when he does he experiences disorientation as one would expect.
What I propose is this: Reading Steiner acts as a constraint on the evolution of timelines. Reading Steiner is, in fact, the Attractor Field. The reason you can’t change too much is because Okabe has to come through any timeline shift with his brain intact. Therefore, his life will look pretty much the same afterwards, with only the equivalent of two days worth of change, even if you send info back in time ten years and destroy Akihabara. That explains the somewhat uneven enforcement of the Law of Conservation of Interpersonal Relationships – it’s not all interpersonal relationships that have to be conserved, just Okabe’s. This leaves us with no explanation for why Okabe is so special, unfortunately. And it’s still a mystery to me why John Titor thought Makise Kurisu was a CERN spy. I had been holding out hope that she actually was one, but now that we’ve seen the circumstances of her stabbing, I’m convinced she isn’t.