Phil,
I think she is politically a bad choice because I think that at
some point somebody is going to be able to convince the public that
qualifications DO matter, and that there could be a backlash, a la
with Dan Quayle, against a choice that seems purely political
rather than one that is aimed at least as much at picking a
possible president. In short, my non-political reasons are also my
political reasons.
Specifically for McCain, I think it would disastrously undercut
his argument that Obama lacks the experience and knowledge for the
job, and also his argument to put country ahead of politics, if he
were to make a blatantly political calculation on a Veep who
doesn't pass his own standards as applied against Obama. In short,
it hits him twice: One on his own image of being called to service
rather than grasping for power, and two on his arguments against
Obama's lack of seasoning.