I think Obama had prepared for a moral/religious question about abortion. He planned to duck it by deferring to God – hence the prepared “above my pay grade” line. Warren crossed him up by asking a very precise legal question – when a baby has a legal right to life. Obama didn’t want to give an honest answer to that question in front of this audience (he believes that a baby has no rights until it is outside the mother’s womb) but couldn’t think fast enough to steer the question back to the one he had prepared for. It will be an interesting couple of months.