I imagine someone could write a great book hypothesizing how it would have turned out. I don’t see how there could be another secession without a total societal collapse precipitating it. Everything is just too interconnected economically and infrastructure-wise and people from all over the country have migrated to all over the country. Geographic areas aren’t near so homogenous culturally anymore. The great divide in the country really isn’t North vs South. It is more urban/suburban vs small town/rural.