With regard to the citizen being wholly or partially responsible for his/her government's actions in war -- and by extension is an active participant in that war, I would disagree with your accepted facts, specifically that "Governments are instituted among populations with and by the consent of the governed."

The government is a social machine. A machine can be defined as a tool with multiple parts, each with a definite function, that applies power to achieve some purpose. By that definition, the government, corporations and other bureaucracies are machines, with individuals serving particular functions, but unlike a car motor or a radio, they have no physical form. We assign them ownership of offices, patents, real estate, and other physical things, but a desk is not a government anymore than you are your toaster.

Government is a fiction, obeyed by most because it is easier, obeyed by some because it gives power over the rest. Just because I was born here (and generally accept its dictates based on rational calculations having to do with force) does not mean I acknowledge it as legitimately representing me.

I would go further and say the only legitimate government is a small (though not necessarily limited government) based upon the principle of consensus. Only then can it truly represent everyone. You might say this is unworkable, but the Iroquois Confederacy operated under this model (in addition to a federalized system of local control, which was also consensus driven). In this way, there is a government, but it governs no one because it has no use of force.