Tod Lindberg makes an entirely original point here:
Hypocrisy was the strange charge Democrats decided to make against McCain and Palin: Having run against Obama all summer for his lack of experience and accomplishment, how dare John McCain pick as his running mate someone with (ahem) experience comparable to that of the Democratic candidate for president McCain had been criticizing?
Well, maybe because it is not a sign of the strength of a candidate at the top of a ticket to need the experience of Joe Biden (or Dick Cheney) in order to allay concerns that he’s not quite up to some aspects of the job. And, contrariwise, it is a sign of strength at the top when the nominee can look to the future and make a priority of party-building. Does anybody think that if Obama loses, he will have left his party in a stronger position by advancing the prospects of Joe Biden?
Well, as Lindberg points out, the difference here is that there’s no question what happens if Obama tanks in November: “Fortunately for Democrats, at least they’ve got Hillary in the wings.”