ABC News -- Obamas campaign manager David Plouffes new book tells a story of how the Obama camp was concerned when they heard that the Reverend Al Sharpton would be coming to Iowa in the final days before the caucus. Plouffe writes that he told Obama, I think we should say that if hes coming to endorse Hillary, of course theres nothing we can do.But if somehow he thinks coming here will be helpful to us, the last thing he should do is come to Iowa. This race is razor thin and we do not need a press side show. I asked Rev. Sharpton to fill in the blanks and he told me that a group was trying to bring him to Iowa to deal with race politics. They wanted me to come in period on the race issue and really youd be hard pressed to really deal with that in...