Civil war can be avoided if the country would simply come to an agreement on splitting. It can’t survive as a 50-state entity anymore.
Splitting the liabilities would be a sticking point preventing that from happening.
Let one side draw the boundaries and let the other side have their choice of which “half” they want.
And that divorce will only work if leftists move to leftist states and normals move to right leaning states. There's the rub. A lot of people are too old to move or they like their piece of land where they live and retired. Might have to give them an exception as long as they keep their politics to themselves and they understand they will be surrounded by those who strongly disagree with them.