David Letterman apologized Monday for a sex-related joke he made May 8 about Sarah Palin's daughter. Last week he tried to clarify that he meant to refer to Palin's 18-year-old daughter, Bristol, and not her 14-year-old daughter, Willow. But he directly apologized Monday to "the two daughters involved, Bristol and Willow, and also to the governor and her family and everybody else who was outraged by the joke."Some had called for some sort of censorship of Letterman, but columnist Kathleen Parker wrote how that would be "far more dangerous to the land of the free than any inappropriate one-liner." Parker argued that "the best defense against rude comics is not 'some kind of protection,' but the rallying cry of people who demand more from their society and themselves."