Arriving home from the hospital after being treated for a heart attack, 84-year-old Carol Barnes inched up the steps into her Sunset District home and headed straight for her absentee ballot. "She said, 'That ... Bush, I can't allow him to be president again,' " said her son, Bo Barnes. " 'I want to vote for Kerry to make the world safe.' " Too exhausted to do more than cast votes for president and two propositions, the widow of an Army major signed the ballot and told her son they'd complete the rest later. Three days later, on Oct. 17,...