There are good reasons for McCain to choose her: She's a reformer who stood up against corruption in her own party. She also has a background as reggaler fokes--hell, she's even an evangelical.
But a big issue in this campaign (as in every modern campaign) is the media narrative. What story is the media going to repeat to the American people about all this? Once a couple of reporters/pundits/editorialists decide on a story line, they can harp on that for months, and never mind what actually happens. Remember George Bush as the guy Americans want to have a beer with? Howard Dean's temper? Gore's wooden personality?
All through the Democratic National Convention, reporters were trying to get quotes from and interviews with PUMA voters to better play up the supposed division within the party. It didn't really mesh with what we were seeing on the screen, but it was the only justification they had for a trip to Denver.
McCain, naturally, wanted to blunt the effect of Obama's big speech (38 million viewers? Holy cow) by releasing his VP pick the next morning. He wanted to give the pundit's something to talk about other than The Speech.
But is this the narrative he was hoping for? After slamming Obama for a lack of experience and saying that the most important criteria for a VP pick would be a person ready to step into his office, he chooses someone with even less experience than his opponent. Was that a serious criticism or just fishing for a negative ad that might stick?
And she has a ethics investigation against her going on. And McCain met her once before he offered her the spot. What kind of decision is this?
I realize that he's trying to sew up the right wing of his own party, but I don't think he can win with just his base, not this time.
The media narrative on this--as far as I've seen--has been "McCain has taken a huge gamble. She's personable, but who is she?"
Another thing this brings up is the Republican tendency to fill political slots with people who are not competent to do the job or openly hostile to the duties associated with that position. If you believe government can't function well, it doesn't matter who goes where, and every failure only proves your anti-government bias.
I'm sure McCain believes himself eminently qualified for the presidency. I'm not sure how much he cares about the VP slot.
Then again, Dan Quayle served 4 years, so what do I know?