With that kind of audience Palin's call to duty was meant to please, her internal family affairs will bite back at McCain, no doubt. If you ride on the high horse of superior morals and then the moral zealots must see that moral failure - or what they see as that - pops up in close vicinity to you, both self-opinionated indignation and muddy dirt will start flying around.
To what degree it effects McCain'S chances remains to be seen. I am sure he did not know in advance, and Palin herself probably also did not know. I would pay a hundred dollars for a private photo of their first facial expressions after they learned the news.