I am strongly opposed to affirmative action nominees.
The bench of potential minority running mates is pretty strong, so it's possible that a white guy will lose on the merits.
But there are other factors than merit that have counted in the past.
It helped Paul Ryan that he was young and from the Rust Belt. When he was under consideration, a factor in Portman's favor was that he was from Ohio.
Geraldine Ferraro is remembered as a botched attempt at pandering, but part of the rationale behind selecting Eagleton was that he was Catholic.
It's odd how there's opposition to particular types of affirmative action in politics (based on gender, ethnicity and race) but no one cares if it's based on region.