As Donald Rumsfeld might have put it, “You go with the nominee you have, not with the nominee you might want.” Based on the speech she delivered Thursday night—the biggest of her life—Hillary Clinton and her campaign have decided that she will win or lose based on the strengths and weaknesses that have characterized her for decades. In the end, Clinton failed to transcend that issue. You, the voters, she seemed to say, simply have to accept me as I am in all my pedestrian earnestness—especially if the choice is between me and Donald Trump. The question leading up to...