Will Joe Biden's toughness as a debater be nullified by McCain's choice of Palin?  To give a Bidenesque answer that is remarkable in its brevity:

No.

Well, maybe I should explain.  In the primaries, when Hillary Clinton was the only woman standing on the stage and was surrounded by male candidates, aggressive attacks on her looked mean, even sexist.  But in the primaries you are the only candidate.  You don't have a running mate.  You aren't the Vice-Presidential candidate.  So any criticism is aimed at you and you alone.

In the general election, Biden can spend the entire debate going after McCain, not Palin.  His attacks won't be against her.  And her defense of her candidate is where she could stumble and show her inexperience.  She probably won't get watery-eyed with a nervous attempt at a smile like Romney would have.  But it's hard to defend a candidate when you don't know where he stands.