` ` I screwed up , '' John McCain tells David Letterman for interrupting his visit . He used McCain 's no - show as subject of ongoing joke . Letterman also did n't appear to buy the Arizona senator 's explanation for the cancellation . McCain also discussed Sarah McCain , who 's ties to 1960s ' radical Leonard Cohen .
` ` I screwed up , '' John McCain tells David Letterman for interrupting his visit . He used McCain 's no - show as subject of ongoing joke . McCain also discussed Sarah McCain , who 's ties to 1960s ' radical Leonard Cohen .