During The last American civil war, the North was the economic poeerhouse, and the slave states were relatively poor. This no doubt impacted the outcome.

Today the blue states are the economic powerhouse, and the red states are relatively poor. Should it come to it, I would expect the wealthy states to win.

We hopefully will never find out, though.

I'm actually not. I am assuming other countries would watch that war break out and consider how excited they are about doing that on their own soil. That kind of civil war wrecks the economy of a developed nation, and power brokers in most developed nations are a lot more interested in protecting their wealth than exclusive nationalist ideals.

Practically, I strongly suspect a US that fell to civil war in this current climate would result in the country fragmenting, not entirely unlike the premise of the old "Cyberpunk 2020" fictional setting. DC would, for example, find it remarkably challenging to hold a California that blatantly broke off from it, especially if the federal military resources of that California defected. Especially if it caught allies in neighboring states upon that occurrence.

The end result would be no real "winners;" it'd be the implosion of the United States of America as a national unit into something more approximating some agglomeration of the pieces outlined in https://www.twincities.com/2013/11/16/which-of-this-writers-....

But even if the end result were (not unlike the last American civil war) a reunification with new laws... The US lost about 2 solid years of its GDP to war. That's not good for business and would encourage those with resources to lose to expend them stifling their own domestic "purity" nationalists.

Proponents of free society should hope the regime loses.