re: If the Borderland states left what would happen to the rest of the US

On I 44 going North from Wichita Falls into the Lawton Fort Sill area do you sense a difference once you cross the Red River. I sure don't.
Same thing with I-40 and I-35
I know for sure with I-40 only difference really is that is becomes greener but not with the people not culture
My grandmother's sister my great aunt lives in Sayre just outside of Elk City
The difference between the people of Sayre Oklahoma and the people of the Texas panhandle is zero
As most of the people there have relations in both states and going into New Mexico and Kansas

I lived in Denton and up towards Krum and Ponder
Used to spend time in Pottsboro which is right on
Lake Texhoma
Same thing as most of the people there have families on either side of the Red River