My guess is that Obama is interested in smacking the Church. Otherwise it would have been very easy to pick any contributor in the Dem party for the post, as long as the person wasn't outrageous, say Sean Penn. But no he is looking for pro choice Catholics to wave his abortion and social positions in the Church's face. Maybe he's looking to start a schism and make John Kerry the new Henry VIII.
Chuck Colson would be a good pick.