Will the USA remain a Union or break up into several different nations?
What I think and what I want are two different things. I think it might be possible that one or more parts of the USA decides it would be better off on its own, and the other parts would choose not to contest the issue. People talk a lot about Texas in this regards, but I think California and the other West Coast states would be more likely candidates. As a Texan I can tell you that few people in Texas would be willing to form battalions of volunteers to march over there and force them back into the Union. However, if it was the other way around and it was Texas wanting to leave, I cannot really see anyone in California, New York or Illinois coming over and forcing us back into the club at the point of a bayonet. I suspect the response would be ‘good riddance’ on all sides.
Why I think it will be California and not Texas is that the people of California have become much more politically radical. Texans talk (or more accurately joke) about leaving the Union, but few are actually serious about it. Such an action would be radical, and Texans are not radical by nature. I compare it to the designated driver; everyone likes the idea but no one really wants to do it. California on the other hand is much more radical showing a willingness to embrace profoundly radical political choices.