John McCain, you don't mess with David Letterman. The Republican presidential hopeful was supposed to appear on

The Late Show Wednesday, but Letterman opened the show by telling his audience that the Arizona senator was suspending his campaign and "racing to the airport" to fly back to Washington and help with the economic crisis. Rolling with the punches, Letterman brought on MSNBC's Keith Olbermann at the last minute to fill in. But that's when things got sticky. During a commercial break between Olbermann's segments, the control room noticed video of McCain being miked up for an interview with Katie Couric for the CBS Evening News, and of course, Letterman ran with it. "He doesn't seem to be racing to the airport, does he?" Letterman asked as the live feed continued, later joking, "the road to the White House runs right through me." Olbermann got in on the fun, too. "I think he dissed you," he said. "Or the other possibility is that [Couric] has all the money that's required to fix the economy. If that's the case, then I'm voting for him." Earlier in the show, Letterman had praised McCain's heroism during the Vietnam War, saying "I have nothing but the highest regard for this manwe're in short supply of actual heroes like John McCain." We wonder how he feels about him how. Watch the video below to see the whole crazy thing unfold. Letterman's praise comes at the 1:24 mark, and the live-feed hijinks begin right around 7:00. ( You can see even more of Dave's rant in our Online Video Guide.) What do you think of how Letterman handled the situation? - Adam Bryant