We could carry the division just a little further. Like dividing the country into “red zones” and “blue zones”.
Divide the country up by congressional districts, and those that voted “red” in the last election would be in one zone, regardless of state boundaries, and the ones that vote a consistent “blue” put in a number of sometimes widely scattered zones, sometimes multiple zones within the boundaries of one state, and some zones joined between adjacent states. The “red” zone, which would be nearly contiguous, would still maintain the statutory delineations between the states as they existed before, but in many instances, it may be necessary to relocate the state capital, as many of the current locations of state capitals are also in hopelessly “blue” zones, And of course, it would be necessary to relocate the center of the Federal government, simply abandoning the existing structures, perhaps to Oklahoma or some other reliably “red” part of the redrawn map.
The Constitutional form of government would be reaffirmed in the “red” zone, and a very strict border policy set up between the larger “red” zone and the various “blue” zones.
The “blue” zones could then set whatever sort of cockamamie set of rules they want to be governed by, but they would not be allowed to practice those rules outside the “blue” zone. If, for whatever reason, they find themselves in a “red” zone, they have a choice of two - return to a blue zone forthwith, or be subject to arrest, trial, probable conviction and sentencing for “harboring plans for government overthrow”.
We have an example from history and even current events. East Germany and West Germany existed side by side for several decades, and we have the dichotomy of North Korea and South Korea before us even today.
The Constitutional form of government would be reaffirmed in the “red” zone, and a very strict border policy set up between the larger “red” zone and the various “blue” zones. And there is the rub.
No nation or nation state in human history has been able to successfully carve out its own niche and separate itself from the surrounding peoples without a strong military to back up the separation with both violence and force.
It is "government" reduced to its core - there must be the law of war to govern the action of independence itself.
The day may come where a state like Texas decides it has had enough, and the governor or the people launch their own National Guard or citizen military into action.
It may take a lot of force, or it may take less - it depends on how strong the other surrounding states or the Federal government itself is at the time. To put it another way, if the entire Federal government were in collapse, the states that wanted to could more easily declare their independence (see: Soviet Union).
When the South succeeded from the North, the North was far from weak. In fact, it was much more populous and industrial than the agrarian South.
We live in interesting times.