As far as I can tell the exchange went pretty much as expected. I share some of ERV's concerns about this exchange. I would phrase my concerns differently: Whether or not any deities or other supernatural entities exist or whether or not they believe in said supernatural entities has little bearing on whether or not someone can do a decent job as President. The fact that this is the second exchange focusing on religion while the proposal for a Science Debate has been ignored makes this all the more irritating. That said, in practice the questions were much more relevant than I expected. Only a small fraction were about explicitly religious topics.
Overall, the predictions of Mark and Aaron were pretty accurate. A few highlights:
When asked when he thought human life began Obama dodged the question. He gave a reasonable moderate position about abortion. But he did not answer the fundamental question.
Obama felt a need to say that he believes that "marriage" is a "sacred" union between one man and one woman.
McCain demonstrated once again that he is not the candidate of science. He once again repeated his caricature about "3 million dollars to study bear DNA. It has been already established that this is both an inaccurate description of the research in question and that the research was money well-spent. (See also Orac's take on the matter)
McCain also talked briefly at one point about how modern communication had changed many things. He stumbled a bit there, was redundant and not to the point. It might not be fair to attribute this to his lack of technological know-how but I'm going to tentatively do it. Frankly, the only way it could have gotten much worse is if he had talked about how the internet isn't a truck but a series of tubes.
Overall, I think that McCain came across better. He seemed more prepared and was more charismatic. He answered questions faster with little bullet points. Obama attempted what may have been more nuance but came across at times as plodding or pedantic.
I expect that more detailed (and less biased) analysis will be available soon at The Presidential Debate blog so you should go over there (especially because my twin runs it).
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