Beginning last Sunday, ABCâÄôs âÄúThis WeekâÄù took a step toward preventing its guests from being ridiculed by John Stewart by fact-checking its guestsâÄô statements. PolitiFact.com will review guestsâÄô claims from the Sunday morning show and post the results on the âÄúThis WeekâÄù Web site. This is a welcome attempt to combat a major flaw in broadcast news, which often have little choice but to allow guests to play fast and loose with the facts. Real-time fact-checking is almost impossible. On March 28, for example, CBS News was forced to follow up its Sunday show âÄúFace the NationâÄù with an article on its Web site rebutting two claims that Rep. Michele Bachmann had made on the show. She was allowed to claim falsely that the government owns 51 percent of the American economy and she also erroneously attributed a dramatic survey to the illustrious New England Journal of Medicine without challenge or correction. Using PolitiFact could not only correct these mistakes after they are made, but it may also improve news credibility. It will pressure public figures to stick to the truth on TV. It would carry even more weight, however, if news shows devoted an on-air segment to correcting previous falsehoods. Though ABCâÄôs new relationship with PolitiFact is promising, the showâÄôs viewers will still have to actively seek out the corrections rather than have the show present them openly on air. The debate about factuality cuts to the core of journalism. The role of the news media should not merely be to provide public figures with a platform; the media must above all be critical and hold them accountable. So long as no one is challenging or following up on publicly broadcast claims, itâÄôs not really journalism; itâÄôs just another politician with a microphone.