I don't think there's a credible threat to civilization, but perhaps a credible threat to our prevailing thoughts on governance.
There is no good justification that the people of Los Angeles should have to live under the rules and cultural customs of Mobile Alabama. Nor should the people of Mobile Alabama be forced to live under the rules and cultural norms of Los Angeles. As long as we re forced to toggle back and forth between which group is forcing the other to live under their own preferences there cannot be peace.
The separation you are seeing is real, but it's not negative. The path forward is more freedom, perhaps even separation.
The black population of Mobile would be more free to run their schools the way they want, including perhaps things like having prayer in class. If Alabama closed its borders to undocumented immigrants the wages of poor blacks would likely rise due to reduced labor supply.
There are examples of federal systems where things that can be agreed upon are shared at the federal level, and things where disagreements cannot be reconciled are managed at the state level.
One of the ways we've gone wrong as a society recently is thinking that there can only be one way, and everyone has to adhere to it. People need to be allowed to disagree, because everyone will find themselves on the side of "wrong" (i.e. less optimal for achieving one's goals) at some point.
We have states openly talking about secession. Of course they're not serious yet, but it's like dropping the d word in a marriage, it can't be undone. I predict it won't get much more violent than we've seen over the course of the last year. And when the divorce does happen it will seem inevitable.
There is no good justification that the people of Los Angeles should have to live under the rules and cultural customs of Mobile Alabama. Nor should the people of Mobile Alabama be forced to live under the rules and cultural norms of Los Angeles. As long as we re forced to toggle back and forth between which group is forcing the other to live under their own preferences there cannot be peace.
The separation you are seeing is real, but it's not negative. The path forward is more freedom, perhaps even separation.