I remember when people said that in the 1850's. There were even reasonable proposals to buy all the slaves so as to free them. It would have been wayyyy cheaper! Wonder why they didn't do that?
That's not the case today.
Today we have a thousand differences that go to the core of who we are... a ‘hot war’ would be insane. It's be like dying over which ice cream flavor was best - chocolate or strawberry...
Totalitarians and free people can't compromise. It's not possible.
The best choice is to peacefully divide the country. Pass a 'divide the country' amendment and let each legislature in every state vote on it...