Herman Cain stuck around for three segments on tonight's Late Show, during which a noticeably "I'm not here for this" David Letterman listened to him give rambling half-truth answers to questions about everything from his "999" economic plan, to his smoking campaign manager (who was there, smoking), to the sexual harassment allegations that have mired his campaign as of late. A clip of Letterman and Cain's tense discussion related to the sexual harassment scandal is above.