Probably the side that knows how to get food, keep the plumbing working, keep the power on (at least as long as the fuel lasts), and build things.
That would be my guess.
This will be metro chaos vs rural with guns & food .
First to go should be the bridges across rivers to the the major cities. Ever see the movie where New York City becomes a prison?
If Pennsylvania isolated Philadelphia it wouldn’t be a red state.
If New York isolated NYC....
If Massachusetts isolated Boston...
If Maryland isolated Baltimore...