This YouTube video juxtaposes the comments of Mr. Obama and Mr. McCain from their respective interviews with Rick Warren on August 16, 2008 (they did not debate each other but sat with him for individual question-and-answer segments, sharing the stage only briefly). Obama's response is first. I couldn't help noticing that he took a lot more time to be far less clear. I did not get to watch the entire program (I hope to in replay), but from what I have so far heard about it from others, what you see here is representative of the interviews overall, reflecting a directness and precision from McCain that suggests he is far more comfortable with his views and his ability to articulate them than is his opponent.
Just listen to the applause of the crowd when he answers the question about when a human being should be afforded the protection of law. This man is ardently pro-life and not afraid to say so.