It's no secret that everyone is weighing in on politics these days, from David Letterman to Barbara Walters and the esteemed ladies of "The View," who, as the New York Times pointed out today, have had Barack Obama, John McCain and even Bill Clinton on their couch, with McCain clearly getting the toughest grilling. But should film critics be weighing in on the presidential race as well? It's no secret that America's leading film critic, the Chicago Sun-Times' Roger Ebert, has been on quite a roll lately, writing a series of barbed commentaries about GOP vice presidential nominee Sarah Palin....