This is really a very silly article. For one, because the deciding lines are not like the 1860s with state loyalties as strong or stronger than national loyalties. People for the most part line up along ideological lines that in physical geography is demarcated by urban vs rural. Most states will have large groups of adherents to both sides within them making it a true civil war rather that a war between states.
Second is that the break up would be driven by half of the country wanting just to be left alone by the other half. The animosity would be like a divorced couple where one side just wants to get away from the relationship and the other wants retaliation for what they sense as an abandonment. The “Texas Republic” of this story wouldn’t be looking to conquer California to reunify the country, but defend themselves and prevent LA, SanFran, Chicago, New York, etc. from imposing on them.
I think such a conflict would be very tough on urban dwellers as much of the supplies a large city depends on could be blockaded by damage to the infrastructure. Country folks being more self sufficient would withstand the deprivation better while in the urban areas the armed and aggressive would scavenge first from their unarmed and passive neighbors before foraging out further. When the urbanites do make their way out into the country they will find the country folks more often than not armed and having greater community cohesion with neighbors banding together to protect what they have. In the end the makers will win over the takers, but the victory would be terrible and ugly and a violent conflict always something to be avoided if possible.
“The “Texas Republic” of this story wouldn’t be looking to conquer California to reunify the country, but defend themselves and prevent LA, SanFran, Chicago, New York, etc. from imposing on them.”
And possibly bringing the parasite populations in Austin, Houston and DFW to heel.