If you can successfully blockade an interior group, sure. But that interior group has the ability to strike back and away from their interior that they want to

If you can successfully blockade an interior group, sure. But that interior group has the ability to strike back and away from their interior that they want to hold. America's infrastructure is totally not hardened. The millions in prisons also make for a potential pool of manpower. All I'm really saying is any actual conflict would play out a lot different than the real civil war we had, or any of our foreign continent excursions where the enemy can't really strike back.