I can't imagine the "Red Dawn" scenario of Russian troops invading and occupying US territory. If anything, the goal would be to knock out critical communication/shipping infrastructure to effectively disrupt all normal activity--can't buy or sell, can't get food, can't depend on modern mass communication to organize and maintain order.
Alongside that, the use of modern weapons to do serious damage to centers of power would speed up collapse. That's the goal if your intention is to hit us at our weakest point: catastrophic societal collapse.
If it's our military against some other military, we've got odds as good as anyone else (and almost always better). But if you've knocked out electronic commerce, disrupted civilian use of things like cell networks and internet access, and made it hard enough to get food on supermarket shelves, all those armed people aren't gonna just keep calm and carry on while they're hungry and several cities are burning.
Sure, it's probably a bit too "straight-to-Netflix" but it's much easier for me to imagine someone applying force at the points we're weakest and letting things fall apart than facing off plane vs. plane, ship vs. ship, and tank vs. tank on the battlefield.
But in rural areas, people would just plant a bigger garden and slaughter an extra hog or cow and dip into the canned food in the cellar. They'd also load their empty shells and sharpen their rifle skills.
When it comes to zombie attacks pointy sticks seem pretty effective anyway.
As much as I enjoyed the early seasons, I understand that it was always the goal of the original author and the showrunners to make it more about people being people in extreme circumstances. If it was decades earlier it could just as easily have gone the Fallout route and used nuclear war/radioactive hazards/mutants/etc. as the backdrop and the stories could have stayed 95% the same.
I watched a few of season 2's episodes, but gave up pretty quickly.
The problem is that, even with 393 millions of guns, USA can't stop recurrent fireforests year after year. And this is only an example. Would be naive to think that, as people have a pistol, can't be killed remotely from a million Km of distance. The idea of a foreign army marching in a country and killing people one by one like stormtroopers, is very outdated.
And of course you can always distroy critical areas and then sit and look how the civilians start killing other civilians for water or food. With so many weapons in the table would be even much faster. Is hardly a guarantee.
Not exactly true.
The problem is that nobody wants to pay the money to do so--especially the people who live in those areas.
In addition, you only get to burn those forests once. After that, they are no longer a threat because there is no fuel.
Not necessarily. I bet that the new replacement ecosystem will be, in fact, much more flammable. The water has quit the area.
You simply can't burn a forest to the ground twice without growing another forrest in between.
Also, FWIW under every circumstance that isn't some kind of military invasion phantasy porn I generally look less positively on our relationship with guns.
[1]http://www.smallarmssurvey.org/fileadmin/docs/T-Briefing-Pap...