The US now, more than at any time I can remember, seems to be polarized into two groups who absolutely despise each other. Why not be honest and declare the experiment a failure? Split the country in two and go on with your lives.
We're not conveniently geographically separated though, it's more of a rural/urban divide and despite what a lot of people think the two areas actually rely on each other. Try growing corn in a city or educating competent medical/engineering workforce in a small town and you'll run into logistical issues pretty quickly.
When I said “I can remember” I was specifically referring to living memory for me (as a 40yo), not to ancient history going back to the civil war.
I have heard people talking about a potential looming second civil war. When I see Supreme Court justices openly taking sides in political debates I start to wonder what will be next.