It's the incredible level of interwoven left/right, progressive/conservative, urban/rural populations in more or less every state.
More people voted for the current president in CA than in more or less any other state. Yet it is viewed as a "blue" state. The millions of Democratic voters in large cities like Houston or Atlanta may not control their state legislatures, but they are not going to sit by as those legislatures attempt to secede. Rural voters across most states are not going to sit by while their urban-controlled legislatures attempt to secede.
We don't have "peripheral" states here, and we don't have "red or blue" states. We have a mostly urban/rural divide that does not follow state boundaries in any sense at all.
I feel like the lesson from other countries is that the military will be the last thing to go. Public funding of everything else will be sacrificed to keep the military powerful, and leaders will be from the military. That will be a complete breakdown of democracy of course.