Have you even begun to think about the consequences of such a thing? Americans think nothing of long distance travel from one state to another — even within a state, we travel up to two hours a day just to get to work (unlike most other countries where it only takes 4 hours to drive from one side to the other, so driving 2 hours. at a stretch is almost unthinkable).
Because of this, families are spread over immensely vast areas. It’s completely normal for someone to move from New York to Florida to retire, or for an east coaster to move out west for work. In my own extended family, my mother’s siblings live in Florida, Arkansas, Oregon, and New York. They have vastly different political views, yet they all support one another emotionally without struggle. These are normal things for American families.
What you propose would put my family (like so many others) into a minimum of three separate countries, that would very likely hate each other so much that easy inter-country travel would be almost impossible, thus you’d be separating tens of thousands of families from each other. Grandparents could no longer see their grandbabies with ease. Millennials and Gen-Xers couldn’t get home to see their dying Boomer parents.
Not to mention the fact that such a proposition would push the South back into the economic status akin to a developing nation, thus condemning the children of the South to even less education than they currently receive, and destroying any future they might have.
Further division is not the answer. The EU was formed after WWII and has managed to keep Western Europe at peace ever since. It continues to welcome new countries into its fold and was even able to forgive Germany for it’s horrendous genocide.
There is no reason America can’t do the same.