Separate Northern and Southern states in the world wars

What if separate Northern and Southern states entered World War I and World War II on opposing sides?

World War I would likely become a decisive and bloody conflict between them, leaving no unchanged pair of states to repeat the alignment in World War II.

The answer expects a bloody conflict if separate Northern and Southern states enter World War I on opposing sides. It questions the assumption that both would survive that conflict as independent states able to repeat the arrangement. Their rivalry would likely be decided in the first war. The proposed World War II alignment therefore depends on preserving a division that the earlier conflict would probably overturn.