A culture war for the ages. This one would be ugly.
I'd say Robertson would cut into the traditional Democratic edge with minorities and surprise a lot of pundits in doing so, probably winning a slim victory (depending what kind of race she'd run), but the sheer amount of hatred and vitriol that would be flung at both candidates and their supporters would be unreal and could very well tear the nation apart.
Let's hope this never happens.
Robertson wins may be 51% - 48%.
That's kind of what I was thinking as well.
But yeah, a darling of the religious right vs. the poster child for the American SJW... this election would probably get nastier than Trump vs. a socialist. I'd seriously think about asking my work if I could telecommute from some remote village in Alaska that doesn't have TV for two years.
Perhaps the map would look like this?
Bitter partisan divides in PA, VA, and MI in particular. Probably some fights between the two candidates' supporters.