Jonathan Bernstein asks: Sullivan believes that Palin's birth story for her youngest son is implausible. I think he has a good case for that, for what it's worth. As I've read over the last two years, I've seen three possible explanations. The first is the wild one, that the baby isn't really hers; she's covering for someone else's inconvenient pregnancy and has adopted that child. The second is that she was an irresponsible mother, and took terrible risks given the dangerous nature of the pregnancy. The third is that she made the whole thing up, or most of it: she...