Asklemmy

Any country can experience civil war but it requires certain material developments. The US would require a substantial breakdown in shared interests for that to happen. Not just partisan frustrations, there would need to be a fundamental economic split so severe that it pitted states or regions against one another and they could actually act on that. This would almost certainly have to coincide with a weakening of the federal government as well, where the states/regions in question need to push against the federal in order to go in their own direction, for their own interests.

The US Civil War had a material basis like this. The South of course sought to maintain slavery and this was the primary issue, but why was it such a sticking point and conflict in the first place? One clue is to look at what happened to production after the South lost (hell yeah): their plantations were bought up by Northern capitalists and run at a profit. The landless poor, which included basically every freed slave, were forced to work there for very little pay while now needing to pay their new landlords for housing. They became the most abused of the proletariat and racism was kept alive for their marginalization in this market. The ascendant northern capitalists had been doing this kind of thing in bits and pieces and by supporting the halt in any new slave states. The Southern planter ruling class knew their days were numbered and, seeing existential crisis, attempted to carve out a country for themselves to prevent that extinction.

You can imagine that sort of thing developing again during prolonged crisis. Some states and regions may develop very different economies and their ruling class interests may become so at odds that it leads to land grabs, assertions of independence, etc. But that would be a prolonged crisis that changed fundamental regional economics and national economics. It's not necessarily unlikely but it would take decades.