I think the biggest problem for the U.S. is that the states agreed to come into the U.S. under the U.S. Constitution and if the Federal Government reneges on the Constitutional provisions the “contract” would be broken allowing the state to secede.
What provisions could be broken and who would determine if they are broken and if so who would determine the remedy?
What about subdividing into North Texas, East Texas, South Texas, West Texas, and Central Texas, to preserve the Texas identity???