We have a structural problem. Urban voters have less influence. https://ballotpedia.org/Population_represented_by_state_legislators It is extremely unlikely there will ever be a majority in the Senate that will change this structural problem. Rural America is a depressing, and weird, and it is in control of the Federal government.
With a majority in the Senate willing to do something, we could: - Add additional states or split states. In all fairness California should be at least 4. Texas, Florida, and New York at least 2. DC and Puerto Rico deserve states. - Add additional voting rights laws, declare holidays, etc. Prevent the sort of disenfrisement happening in Texas & elsewhere - Add additional seats in the house! Saw a really cute proposal saying we should have like 10,000 to match the same ratio of representatives to population we had when the country was founded. This doesn't need an amendment it could just happen. And then gerrymandering and bribery is basically impossible - Interstate compact for Popular Vote (could happen) - Pack the courts. Controversial but possible? none of this stuff is going to happen unless we really really make it happen. So I'm not holding my breath. But it isn't totally impossible
Other problems with "The Untied States" (read carefully) aside, how would we divvy up the military? Am I supposed to believe Greg Fucking Abbott is going to sign or act on an agreement of mutual defense? He's more likely to try and take you guys over, if China doesn't go for it first. Should I plan to move to a state where there's a lot of nuke silos? Should we start digging our own silos right now? How many Texasbucks does a nuke cost? Brexit went great? Seriously, that's a road to calamity. We're certainly at "disaster" already, I agree, and I understand your incentives, but no. "Fuck this stochastic civil war, let's do it up forreal"
Except it's a rural/urban divide. This is one of the main reasons the West tends to be more liberal overall: for all practical purposes, the hierarchy of the west was established by sea, and the major cities of the west were minor outposts until air conditioning and automobiles. Population in the west diffused from city to country. The east is the same just a hundred years ahead or so, such that the rural areas have less of a link to the urban areas. I think this is reversing. If I can pay you 2/3rds your salary to show up via Zoom? If you'll take 2/3rds of your salary because rent is 1/3rd what it is in San Francisco? You're gonna start complaining that there's no Whole Foods in Barstow, AZ. If enough of your friends do the same there's suddenly yoga studios.
My wife recently poked a hole in my theory by pointing out that having abortion be suddenly illegal is likely to deflate a lot of plans to move to, oh, thirteen states. I agree with her, she's certainly right. But there's also a broad contingent of Hollywood intent on boycotting Georgia, which is saying a lot considering how much production has moved there over the past fifteen years. Here's the thing: industrial production of whatever we're making is no longer tied to resources. It's largely tied to tax incentives and social conditions. For fifteen years it's been desirable for Hollywood to shoot in Georgia and Louisiana, no matter how regressive their governments are. For the past five or six, though, it's been tenuous. For twenty years it's been desirable for Hollywood to shoot in New Mexico. Which has gone from being republican-leaning in my childhood to being California-democratic. Sure - there's crazy there. They elected a libertarian governor (he ran as a republican, things went worse than expected). But in a global economy where broadband and organic food are enough, industry can pull out of a repressive state as fast as they can move in. I think this is going to suck. I think it's going to suck for an interminably long time, and I think it's going to suck amazingly hard. But I also think we're a long way from steady-state. Some jackass on Twitter tried to make this all the fault of everyone who didn't vote for Clinton because of course they did. He further scolded Democrats for only voting in national elections while Republicans reliably vote every time in every race. He wanted it to be true so badly, and so did his audience, that he didn't even bother linking to anything like facts. What he was trying to get to, which is much less hard to scold people for, is the fact that Democrats want their vote earned, while Republicans will vote Republican unless you've lost their vote. That's the question: how many Republicans are ready to opt out? how many will opt out come November? The basic problem the Republicans have is they've been pandering to their base for so long that their base has peeled them off fully to fascism. Most Americans aren't fascist; history would be much simpler if we were. I don't know how this resolves? But I know that if Republicans hadn't been a minority party for 40 years they wouldn't have to do all the shit they're doing just to get elected.
Americans vastly overestimate how deep their divisions are. It's actually pretty normal for countries to have real, viable separatist movements within them, and the US is nowhere near that. Quebec almost left Canada in 1995, Scotland almost left the UK in 2014, Germany was split into two separate countries for almost half of the 20th century, Korea is still two separate countries today, Catalan may or may not be part of Spain anymore (it's been a while since I checked), and nobody is even really sure how many Chinas there are. If anything, what's remarkable about the United States is how united you are, despite being a large group of people spread out over an entire continent. The vast majority of Americans speak the same language, follow the same religion, and -- perhaps most importantly -- identify first and foremost as "Americans". The fact that some of you vote for the "Have you ever hated the poor?" party and some of you vote for the "Have you ever hated the poor, on weed?" party is far less significant than the terminally online crowd would have you believe.
Importantly, the divisions are cultural rather than geographical. With the examples you list there's an existing border to trace with a bright red line whereas in the United States our divisions basically reflect electoral gerrymandering. Arizona exists as a state largely because Barry Goldwater strove to create a conservative paradise there. It's fair to say that the conservative demagogues we have in our south are attempting to repeat the process... but since they aren't starting with an uninhabited hellscape they're tripping over existing demography. You're right, however, that the Keyboard Kommandoes are definitely making much ado.