All eyes are on Palin and Ifill, but the real challenge is for Biden. Leaving aside that he can’t be himself because himself (as I explain here) has been wrong on every significant issue for the last three dozen years, the format tonight calls for two-minute answers. As Judiciary Committee hearing watchers know, Biden can’t get a question out in a 10-minute time allotment; how he gets answers out in two is unknowable. Of course, there’s no rule about being coherent, so …