Republican running mate for his seat? Washington (CNN) – Sen. John McCain's campaign is out with a scathing new ad against the senator's Republican primary opponent, calling J.D. Hayworth among the "dumbest" people previously in Congress. Now Hayworth's campaign is firing back, suggesting the ad is shameless. Hayworth's campaign also claims that McCain – a celebrated war veteran – is using America's World War II heroes "as a political tool
