Responses to my post from yesterday seemed nearly unified in agreeing that it is immoral to kill someone who has a 5% likelihood of someday killing you in the future. Most people agreed that in order for self defense to be a moral act you need the danger to be more immediate. And if you use the 5% threshold of danger you can justify killing just about anyone now so they won't accidentally drive over you in their car later.
Most of you agree that if someone pulls a gun and says, "I'm going to shoot you after I rob you so there is no witness," you would be morally justified in killing him first if you can manage it, even if he hasn't started to pull the trigger yet. But you wouldn't be morally justified in killing people who own guns just because they might someday use them on you. That's what the consensus seems to be.
But what if your odds of being killed by one individual, one year from now, are 99%? Is it moral to kill that person now if any delay in doing so makes it less likely you could get him before he got you next year?
If you say it is moral to kill that person to save yourself, because a 99% chance is very different from a 5% chance, then I would argue that morality isn't part of your calculation. You're simply making a judgment of what is practical, both for you and for society.
If you say it's not okay to kill someone who will almost certainly kill you sometime next year unless you get him first, you are highly moral indeed.