Bill O'Reilly, David Letterman High Five Over Iraq War (Video)

John Paul Filo/CBS Bill O'Reilly and David Letterman joked around on the Late Show Thursday night -- a far cry from their prior, tense appearances.our editor recommends'Spider-Man: Turn Off the Dark' Cast Performs on 'Late Show With David Letterman' 'Two and a Half Men's' Ashton Kutcher, Jon Cryer, Angus T. Jones Present Top Ten List on 'Late Show With David Letterman' (Video) (In 2009, Letterman called him a goon; in 2006, he told him, "About 60 percent of what you say is crap.") VIDEO: The Biggest Failed Jokes at the Academy Awards Thursday, Letterman and O'Reilly debated Occupy Wall Street and the Tea Party, with O'Reilly telling him he made "an excellent point" and Letterman politely thanking him. After O'Reilly admitted the war in Iraq "should not have happened in hindsight" because the country did not have weapons of mass destruction, Letterman stood up for a high five. PHOTOS: The Most Talked-About TV News Faces "Up high! Come on, up high....come on, Billy! Come on! Come on!" Letterman enthused as O'Reilly shook his head. "I'm not high-fiving you on a war! I'm sorry...." O'Reilly replied. "We're having a good conversation, sit down." PHOTOS: NY City Power List Finally, O'Reilly stood up and gave him a high five. "Yeah!" said Letterman, before joking: "No wonder Cheney won't come on your show. Mr. Grouch!" David Letterman Bill O'Reilly Late Show with David Letterman