Redshift, Blueshift . . .

I wrote a story by that title a long time ago and I've been thinking about the ethical dilema it posed. I thought I'd bring it up here so maybe we can have a little discussion about it.

The basic premise of the story--it was science fiction--is that the narrator of the story figures out a way to end a long and bloody war with an alien race. Unfortunately, his way of ending the war will result in over a hundred million human casualties. But, afterwards, the war will be over. It had been going on for years with neither side getting an advantage and with the sheer power of the attacks growing and no chance of it ever coming to an end, until this happens.

It's kind of complicated, what happens in the story--basically he figures out that we had been attacking ourselves because we were using a technology we didn't totally understand. Ships we sent to attack the enemy were actually being sent back a few months in time, and everything was so distorted that they didn't know they were attacking earth--and we didn't realize it was our own ships. The commander of a powerful fleet sent to avenge a devastating attack figures it out--it was his ships that came and wiped out all those people and created all that destruction.

Unfortunately, if he aborts his attack then someone else will. The nature of time travel--in this story, anyway--the attack happened, so it will happen. If he doesn't do it, then someone else will, and it's entirely possible that it'll be an alien race that will sort of pop up to fill the void that gets created when he aborts. So, if he continues he'll kill all those people, but since he has the evidence now to prove this is what's happening, the war will be over. If he doesn't, then it'll be out of anyone's control and the war can continue until humanity is wiped out totally. He'll basically be creating an enemy--one that it will turn out has always existed.

He goes through with it. The story is both about the attack, and the after math, where the military decides what to do with him--is he a hero or not?

Here's the question, though--what would you do, in that situation? Think about it, and let me know. I'm curious.