The state has no monopoly on force. The US armed forces are made up of US citizens. They are sworn to defend the constitution against all threats, foreign and domestic. That could include a president and congress, it could include corporations, it could include Canada.

The narrative of armed citizens operating in a structure to defend citizens and the constitution works fine if you don't have armed citizens operating in a structure to defend citizens and the constitution.

If you lose hearts and minds of one group armed US citizens (the military), why is your group of armed citizens any more justified?

If you don't lose it, why do you need the armaments?