+100. I can't be a big help here (living abroad and being almost completely Internet-based), but waitng for the result with great interest. BTW - what is so special in that Mississipi county, that gave Obama only 2% of white vote? Even by Deeep South standard that's something
I can't necessarily speak for RGriffin, but when I calculated for Mississippi, I used some constant assumptions across counties, a constant black and white turnout percentage across the state, and constant minority percentages in the breakdown (I think it was 96-4 for blacks, around 75% or so for Hispanics and Native Americans, etc.) Whatever is left would be my calculated white vote.
However, if for some reason a county had a black turnout that was a lot lower than the state average, or for some reason Romney did better with blacks (I don't know why that would be the case in Mississippi, but there had to be some county-to-county variation), it would make the calculation undercount white votes for Obama.
