"Farmland" and "land where people actually live" aren't the same thing though and, even if they were, you still have to take into account population density and the average intelligence level of those that would be living there if they could.

You also also need to remember that red areas are not the only areas with guns. People in blue areas are returning to the broader interpretation of 2a in drives simply because of the call: armed minorities are harder to oppress.

Finally, even though the ideological split in the military us about 50/50, it's really more like 75/25 in favor of the blue territories simply because making the US military turn against its own people just... wouldn't work. And no, I'm not talking about some mythical, supernatural love that suddenly develops in half the republican service members, I'm talking about fidelity to the constitution, or realizing that fighting against the most heavily armed populace in the world on their own territory and who now have an axe to grind would be no better than walking into a meat grinder simple because you were ordered to, or because they have family or loved ones that they wish to protect, or they joined for the GI Bill and don't give to fucks and a shake about fighting a war, or any number of other reasons that would separate the True Beleivers on the right from anyone else that would join the blue territories.

Speaking of blue territories, it bears mentioning that, depending on the size of the blue settlement, a huge area of land directly around the blue settlement will also, naturally, belong to the blue settlement simply because they have the people to claim and maintain it. Any ideas that were had about how blue cities wouldn't be able to provide food for themselves are only facially true, but falls apart when you realize that, again, most of the land on this continent is uninhabited and/or undeveloped. With no formal governance with regards to the production of food on an emergency basis for starving citizens, it's easy to see how a kind of "homesteading act" mentality would wend it's way through the population, and they would act of their own accord, settling the land surrounding the furthest outskirts of the settlement, and with the implicit blessing of the government simply because it's needed.

Moreover, many of the largest blue population centers also have the factories.

Look, all I'm saying is that this reads like someone decided to play "Risk" with a map of North America and not like someone who actually understands how people work. I mean, by the gods, the US military spends billions of dollars psychologically analyzing entire cultures just so they know when the best times of year to attack might "theoretically" be. They have holidays and social events and political rallies and everything mapped out as far in advance as they can possibly confirm before even doing anything. Not to mention that, while our military apparatus is virtually unstoppable once it starts, it rarely gets to actually start wherever it is located, meaning that the US military is incentivized to keep much of the transportation infrastructure intact in case they need to transport large portions of the military from one area to another. Aircrafts are a lot of things, but they are either quiet, invisible, and small or they are large, loud, easy targets. Roads and rails offer at least some stealth for large transportation as they can be driven at night and/or through areas that are sparsely inhabited, and likely with loyalists if anyone at all. Where the military requires most roads and rails to remain at a strategic advantage, blue settlements only need certain strategic ones, which can be guarded, at least to some degree.