The Founders thought standing armies were a threat to liberty, which means they surely would have thought that standing private armies constituted the same threat. Self-preservation and self-defense might be natural right, but even in Heller the Supreme Court indicated that there could be reasonable limitations on gun ownership.

To answer the scoffers on the Left, though, imagine what an American revolution—the exercise of first principles—might look like in the twenty-first century. The government, or a branch of it (most likely the executive) becomes destructive to the ends for which it was established. It tyrannizes the people, takes their property, deprives them of their rights, destroys their lives. A revolution, or an abolishment of that government, would likely not be a civilian undertaking but a military one. Working in conjunction with other branches of the federal government and perhaps some state governments, the military would effect a coup d’état.

It would likely be a kind of civil war, and civilians would likely be caught up in it at some point. Perhaps they would form local militias to defend their homes and businesses. Perhaps they would volunteer their services to military commanders or state police forces. Perhaps they would simply want to ensure the safety of their families.

To do any of that, they would need to be armed. Just as the Founders envisioned.