1. The state isn't sending the soldier to die, it's sending them to fight. They may die, but dying isn't the purpose. The state would very much prefer them to not die, in fact.
2. Nothing bad happens if we just don't kill the serial killer.
The "state" does not have a preference, states are conflicted by nature. Probably would not take much effort to find examples of serial killers who were not killed doing something bad, killing another inmate, killing a guard, getting out on a technicality, etc, etc, etc. Yes, if we lived in a utopia things would be perfect and you would not be ignoring the point.
My definition of utopia allows for disagreement, my issue was with his methods, avoiding the original point and not the disagreement. I never tried to justify anything, at most I expressed a preference for killing serial killers over having wars.
Why? Because killing serial killers is good, and having war is bad?
I think the person you were responding to had a more utilitarian view. When war happens, the death of conscripted young people is unavoidable. It's kill or be killed. We prefer wars not to happen, and people not to die, but it's not a choice.
Killing a serial killer who has already been apprehended is a choice. And it's here that we can actually start weighting options and see what is better for the society, bringing up possibilities of wrongful convictions, Blackstone's ratios and second order effects of the death penalty.
I made no such judgement, just sort of but not really implied that I would rather serial killers die than random people and then admitted it in a purely intellectual pie in the sky sort of way—killing serial killers will not end war. Plenty of examples in history when a draft was used in times other than kill or be killed, when it was political. It is ok for the state to kill its citizens for political reasons but only when those political reasons are war? At what point does civil unrest become civil war? When that line is crossed the killings suddenly become OK? What if it were treason instead of murder and the execution of that traitor could help mitigate civil war and far more death? That comment opened a massive can of worms, it is more complicated than ideals and what we would like.
1. The state isn't sending the soldier to die, it's sending them to fight. They may die, but dying isn't the purpose. The state would very much prefer them to not die, in fact.
2. Nothing bad happens if we just don't kill the serial killer.