It’s completely academic since no foreign military will set foot in the continental US, but a lot of our gun nuts are former military, and the ones who aren’t still go to the range, join militias who run drills etc. This is literally their dream scenario. My uncle has a secret room in his house which not only has several guns and extra ammo, but also a crossbow, gas masks, items for barter. If we have a problem it will be like Italy’s years of lead or another civil war. It won’t be a foreign invasion.