That's fine. But how do you technically in a real way protect a Nation that is possibly being eaten from the inside out?
The philosophy becomes drivel if the military waits on the coasts to protect from invasion from abroad, as the 'enemy' chews up the territory at their back by infiltration.
Not advocating coups or martial law just looking for sense in philosophical debates. You can't defend a Nation that's merely an ember from a fire you didn't touch domestically.
The Nation is its people? And most of them, if it's the USA, live in the country, not outside it.