Well, try to imagine what it would be like if each and every state could leave the Union over any issue that some politician got the populace jacked up about?
First would be the Confederacy, but then other states would withdraw from the “Union”, and the Confederacy also.
Then, North America would have many smaller states with different ethnic concentrations being agitated by politicians; similar to the Balkans.
How’s that working out for them? I believe the outcome is knowable to most people.
I think you’re forgetting that the recent difficulties in the Balkans stemmed from the attempt by the Serbs and former Yugoslav army to prevent certain peoples and regions from seceding. It’s the same as what Lincoln did, except the “union” lost that particular bloody war. But the analogy is bad for another reason: You simply assume the inevitability of a Balkan type split rather than a peaceful separation like that between the Czech and Slovak republics. Separation can work out just fine without a tyrant grasping to hold dominion over those who reject his claim to rule over them. You can speculate whatever makes you happy, but the course of alternate history is unknowable.