I think I spelled it wrong...

The link is relevant because it gives you background on the larger issue at hand, including your own argument. It is not theories, it is current real life debate and resolution.
One act is enough to make someone a combatant. In a conflict, again, civil law does not apply. That is part of what makes it a conflict. That is accepted as Customery International Law, including UN resolution, which I have already pointed out.
What you are arguing for can only be if we establish a One World Government, and then treat everything as law enforcement.
You can not seem to understand that states are beholden to each other as a courtesy, not because they have to be. When courtesy lapses, this is where conflict begins. This is why civil law does not apply.
These are not my ideas, these are based in international convention.