In Depth

McCain Cancels ‘Letterman’ Appearance

Presidential candidate Sen. John McCain, R-Ariz., who said he is suspending his presidential campaign to focus on the economic crisis, canceled his appearance on tonight's "Late Show With David Letterman.”

A spokesperson for "Late Show" said Keith Olbermann, the liberal host of "Countdown" on MSNBC, will fill the hole in the CBS show's lineup left by the McCain cancellation.