Why is Charlie Gibson retiring?  

Is Charlie Gibson retiring because he has become so biased to the left as exhibited by his attack interview of Sarah Palin back during the election? No, that can't be it because he works for one of the big three highly biased to left networks. Maybe, just maybe, as exhibited by his being totally unaware of the Acorn scandal awhile back, the several times during his show that he has asked basically the same question of an ABC "expert" again and gotten the same answer, and the more and more numorous errors he makes during his broadcast, it is that he has early alzheimers and has to retire before it becomes too bad.