Moments before Sen. John Kerry shows up to campaign for a local politician at a backyard rally here, voter Sue Borden wrinkles her nose at the mention of the man who lost to President Bush. “You get one chance,” the Democrat tells a reporter. “If you can’t win, then it’s time to let someone else try.” But less than an hour later, after she meets Kerry and listens to him deliver an impassioned speech from a wooden deck, Borden softens and says she would consider voting again for the Massachusetts Democrat. “I always liked what he stood for but felt...