30 years spent living in the deep south. Maybe it wouldn't hit 51% but I guarantee you it would be a lot higher than 10%. You're also assuming equal voter turnout and no voter suppresion. These are both, shall we say, optimistic.
Of course, I'm pretty sure there are racists in the south - as well as everywhere else, this is a common mental malady, which, like lice, often manifests itself when proper hygiene is not maintained. However the claim that virtually all white population is so racist as to wish for return of Jim Crow laws feels a bit strong to me. As for voter turnout, it looks like specifically for Mississippi it's not that bad: http://www.governing.com/blogs/by-the-numbers/changes-in-vot...
and actually white voters' numbers are lower than black voters', while overall turnout is one of the highest in the nation - it looks like MS citizens take their voting seriously. Overall, 82% turnout doesn't sound bad at all, and if the hypothetical vote would be on something as outrageous as Jim Crow laws, I would think these numbers would further increase.
