Still, it was a good speech, and a serious one. I don't know if it will help him. We're in uncharted territory. We've never had a major-party presidential front-runner who is black, or rather black and white, who has given such an address. We don't know if more voters will be alienated by Mr. Wright than will be impressed by the speech about Mr. Wright. We don't know if voters will welcome a meditation on race. My sense: The speech will be labeled by history as the speech that saved a candidacy or the speech that helped do it in. I hope the former.