I believe in the absolute right to self defense, and so do all conservatives. It is the closest thing to a guaranteed sacred and holy thing that is not in the Bible. I mean there are lots of examples, the right to self defense isn't the only thing, but it is a holy right, even though it's not explicitly in the Bible.
There's no way to guarantee that you can only exercise this right in accord with any kind of due process. So obv we need to be careful with what we consider murder. It's never murder when we use lethal force in our own defense when it's justified. This has nothing to do with our defect, but it has everything to do with the aggressor and attackers. They started it, they escalated without justification. We have a right to defend ourselves, it's an absolute, natural, inalienable (meaning even if you outlaw it, it still exists) God-given indivisible universal human right. It has nothing to do with laws. Except to JUDGE laws which infringe or abridge it, and especially laws which condemn and punish its justified exercise.
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And so your hypothetical needs only some mechanism to choose between flying the plane into the building, and missing the building, which immediately results in these child rapists—raping children. It's for some reason within your power, it's your choice, your opportunity, to fly the plane into the empty building, which you know will not result in the harm or death of any innocent people. If you don't do this, they all start raping children. I know this isn't a realistic scenario, I'm just riffing off your example, there are better examples if we use our imagination.
What I mean is, don't say, "How could a plane-ful of child rapists start raping children all at once?" ofc it's not an Earthly scenario. I'm more just saying, syllogisms and propositions don't really need to be realistic, you can join terms together that are virtually impossible to imagine or envision, it doesn't make it pointless. So you have a unique opportunity to save hundreds of children from being raped. It requires you to die, by flying your plane right into a building which is vacant and there are no innocent people anywhere nearby, so nobody else is at risk. If you do this, the child rapists will die, and the children will not be raped.
No due process.