Hillary Clinton can change her message, change her campaign manager, even change her hairstyle—but she can’t change the delegate math that makes it almost impossible for her to win the Democratic presidential nomination. In several ways, recent news has been good to Clinton. She continues to win in states like Ohio and Pennsylvania where there are large numbers of white working-class voters. Arguably, her coalition of white working-class and Hispanic voters is equal to Obama’s coalition of white-collar and African-American voters. Obama has been on the defensive lately, dealing with the continuing problem of his former pastor, Reverend Jeremiah Wright,...