There is no way to break up the country state by state.
If/when we have Civil War II it won’t be between the states. It’ll be between urban areas vs. rural.
Take Texas for example. Austin, San Antonio, Houston and the DFW area will be the enemy no-go zones. The rest of Texas will be declared freedom loving conservative areas.
The word I’m referring to is Balkanization.
https://en.wikipedia.org/wiki/Balkanization
You’re absolutely right that liberal enclaves within red states and conservative enclaves within blue states make a pure state-by-state break-up pointless.
To some extent, the situation is analogous to the Catholic/Lutheran divide within the Holy Roman Empire in the 16th century. Eventually, with the Peace of Augsburg they came up with a settlement “cuius regio, eius religio (”whose realm, his religion”) wherein each prince could pick either Catholicism or Lutheranism for his territory. But there was still a problem of a lot of Catholics being inside Lutheran territory and vice-versa. The solution that they came up with was a provision in the treaty that encouraged people living in “hostile” territory to relocate and basically forbidding “exit taxes” or other burdens on them moving.
We are not a nation anymore. So the idea of idea of mutual relocations to weed out political differences might be something to consider. A mutual defense pct like NATO might work. Wipe out the national debt with muti-trillion palladium coins. States can keep or delete federal programs. Social security- ???
Deo vindice