This statement just emailed, perhaps notably, not by a Biden-specific aide but by Obama spokesman Bill Burton:
“I was asked about an ad I’d never seen, reacting merely to press reports. As I said right then, I knew there was nothing intentionally personal in the criticism of Senator McCain’s views which look backwards not forwards and are out of touch with the new economic challenges we face today. Having now reviewed the ad, it is even more clear to me that given the disgraceful tenor of Senator McCain’s ads and their persistent falsehoods, his campaign is in no position to criticize, especially when they continue to distort Barack’s votes on an issue as personal as keeping kids safe from sexual predators,” said Joe Biden.
(Verbal mishaps like these, of course, are precisely why many people were nervous about putting him on the ticket.)