CBS is NOT going to fire David Letterman. But hey, if it makes you feel good to insist that they do, who am I to stand in your way?
No, probably not, but it makes for a good negotiating stance to start out asking for it.
Then the compromise, as we have seen, is an increasing number of more and more "sincere" apologies until, while keeping his job, he is so bruised publicly that he will never tell another Palin joke in his life.
And that is a satisfying outcome.
Then we move on to the next target. The double-standard must die.