Des Moines, Iowa (AP) -- Republican presidential candidate John McCain, once renowned for his jocular sessions with journalists, appeared irritable and at times sarcastic in an interview in which he defended running mate Sarah Palin's experience and campaign ads critical of rival Barack Obama. Meeting Tuesday with the editorial board of The Des Moines Register, McCain was asked why he picked the Alaska governor, someone "who doesn't have a lot of experience." "Thank you, but I disagree with your fundamental principal that she doesn't have the experience," McCain replied before citing Palin's work as a PTA member, city council member,...