Frank Rich on race in race

My Dad and I were talking recently about the results from the Democratic primary the other day. He made the point, that I had heard before, that Latinos didn't appear willing to vote for a black candidate. I didn't mention it at the time, but it seemed an unscientific and stereotypical position. I stumbled across this Frank Rich article that put a little more context into how race has become an ugly undercurrent in the battle for the Democratic parties nomination. Not a good sign...