It seems like there’s a self-selection problem: the non-white Trump voters are voters in Republican…
Theodore Malter

Thanks! You’re absolutely right. I was addressing the narrower question of why a Republican voter would choose Trump over one of the other Republican candidates in a primary or caucus (say, Marco or Jeb) rather than over the Democratic candidate in the general election, and have made a small edit to reflect that. And yes, the confluence of those two factors is probably greater than the sum of its parts.