considering the state of the military technology that the United States armed forces could bring to bear in the hypothetical scenario where our national standing army decides to neutralize the states.
This is part of the point, if a portion of citizens did rise up, the US would be forced to respond either militarily or via some sort of negotiation. If it did neutralize any states or peoples, It would be essential for those remaining to protect themselves, their families, and their communities even if it can only do so at a fundamental level. That ability to provide protection is a natural right and why the constitution protects it.
Can you elaborate on what you mean here? Is this a scenario where, say, a significant portion of Michigan's Upper Peninsula decides to leave the United States, so non-combatants would need firearms to protect themselves from the lawlessness during the war? if a portion of citizens did rise up, the US would be forced to respond either militarily or via some sort of negotiation. If it did neutralize any states or peoples, It would be essential for those remaining to protect themselves, their families, and their communities even if it can only do so at a fundamental level. That ability to provide protection is a natural right and why the constitution protects it.
This is, of course, a philosophical assertion, yet upheld by many different philosophies. The value and preservation of human life are central to Western thought. The argument can be made from autonomy (Locke), Natural law (Hobbes), and even, virtue ethics focused on vocation and common good of neighbor. Freedom of speech, expression, and religion are always asserted and rarely argued. The constitution upholds a set of principles promised to every individual in this land that is not contingent on the Government nor the philosophy of those individuals. The sad thing is, those principles all essentially assert that all human life is valuable, yet our history shows that we have been more than willing to treat some people as sub-human.
Philosophy is a very different theater of debate than law. Legally, our system is heavily influenced by Locke, he of social contract fame. Within the framework of philosophy, we give up some individual rights when we join a collective in exchange for collective protection of those rights. Second Treatise on Government doesn't say "you get all the guns you want." It says "you give up the right to do some things for protection to do other things." What those things are is the subject of law.
Tha is a pretty far extrapolation of what I outlined here. There are some weapons, which no one person is permitted to operate even within a military context, missiles, tanks, drones, etc... require consensus and chain of authority. A means of personal defense as a regulated militia perhaps in its most basic sense applies to the ownership of weapons that a soldier is regulated to carry. Handguns, rifles, shotguns. Personal defense weapons.