I've been thinking about the ramifications to this line of thinking and it seems to negate our whole 2nd Amendment reasoning - an armed populace is anathema to domestic or even foreign enemies.
Admiral Yamamoto is supposed to have said that invading the US of A would be foolhardy because there would be a rifle behind every blade of grass. When he said it our Army and Air Corps were 3rd rate at best and immediately after Pearl Harbor we had no real sea power in the Pacific except for a few carriers. And those rifles behind the grass would likely be lever action 30-30's with just a very sparse smattering of iron sighted bolt actions - not a lot of long range scoped rifles in the 40's. Today we have tons of AR's in private hands and tons more scoped rifles.
Given that our terrain is much more vast than Switzerland, you could still break it up piecemeal and take it one piece at a time, and a large portion of our country is beautiful tank terrain (the whole Southwest and the Great Plains) while other places (mountains, swamps) not so much.
But against a dedicated military force, either our own turned against us under some despot or a foreign power - what good is a bunch of rifles, even very accurate ones? At least that's where I'm seeing this line of thought lead.
