Maybe. Iowans can be frankly honest sometimes, and this may have been one of those instances. No way to confirm it either way...
Sorry, I don't buy it. The phenomenon is real, but the Jackson story is made up. And it's real, not because whites are racist, but because libs are embarassed to admit that they won't vote for the black guy, because they fear being labeled as racist, even if they are not. It's political correctness, is what it is.