I agree. But I believe the states will have factions within them that will make it all even more deadly. The huge cities (LA, NY, etc.) will not be able to feed their populations and it will move into the suburbs and countryside. And that is when they will realize they are not prepared. Country folk are armed and more likely to kill for a cause they truly believe in.
Many on both sides will perish. But I have faith that the Alt Left will lose.
IF a state secedes by referendum the the whole states secedes. You can riot all you want but you are now in anew country. NY and CA would never secede they are to pussyfied and hooked to FedGov™.