PHILADELPHIA - A smiling, energetic former President Clinton (news - web sites) campaigned for Democratic Sen. John Kerry (news - web sites) on Monday just seven weeks after undergoing heart surgery, telling a crowd of thousands that President Bush (news - web sites) and Republicans are trying to "scare the undecided voters" away from the Democratic nominee. "If this isn't good for my heart, I don't know what is," Clinton said of the enthusiastic response from the lunchtime crowd. Democratic strategists hoped Clinton's appearance in the final days of the campaign would provide a jolt of excitement that would help...