Well, that was assuming they actually vetted Palin... this story is so weird it's sort of hard to comprehend:
Yesterday the Internet was buzzing with the rumor that Palin was actually the grandmother of her 4-month-old baby, Trig. The allegation was that the baby was the child of her teenage daughter Bristol, and Palin faked a pregnancy to cover this up. How better to knock down the story that you're a grandmother and your daughter was knocked up than to reveal that you're about to be a grandmother and your daughter is knocked up (and that the girl plans to marry the father of the child)?
That was Emily Yoffe, who has more if you click the link.
I have no idea whether this is good, bad, or indifferent for the McCain for President campaign... but it's definitely strange.
UPDATE: See hilzoy for places not to go. Honestly, I see no political hay to be made here... my mother had my brothers when she was about the same age (18 and 19), so you should read no condescension in my bafflement at the fact that a VP candidate has an underage pregnant daughter. It's just so hard to see how the media will react to this that it seems an odd gamble for a Presidential campaign.