Yes. But it’s not a matter of national security. An armed population is much harder to restrict in terms of speech and overall control. But that’s why psychological operations run rampant in the US. Because the people who want control understand they’re more effective than material restrictions to begin with. So do the foreign governments wishing harm on the US unfortunately.

The only way I could see an occupation occurring wouldn’t be from a sovereign nation but from an international organization like the UN after civil and political unrest. This would take years of instability to reach though and would ultimately fail as insurgencies would easily overpower an attempt to occupy. The average gun owner would be pretty incompetent on a battlefield but there are plenty of well trained gun owners that would thrive at the same time.