Character attacks emerge in McCain-Obama race   Debate stakes higher for McCain as insults mount   McCain calls Obama a liar   Obama: McCain tries to turn attention from economy   Palin criticizes Obama's ties to Wright, Ayers   McCain, Obama camps trade barbs on negative ads   Analysis: Palin's words may backfire on McCain   Quotes from Palin on Obama's ties to Wright, Ayers   Palin ethics probes beset by secrecy and lawsuit