One thing we can be certain of, no matter who Barack Obama picked as a running mate, the Republicans would have attacked him or her. They had a canned commercial all setup and ready to air first thing Saturday for Biden. As Biden was the least likely of four or five possibilities, it's easy to conclude really ANYONE chosen would have been attacked.
For Hilary - too liberal, too bitchy, too much like Bill
Tom Kaine - too inexperienced
Biden - too experienced
Bill Richardson - too much of an outsider, too inexperienced, too liberal
It would have happened no matter what, and that's why Tim Pawlenty's criticisms of Obama and Biden are nothing more than political theatre. Biden represented a reasonable, though unexpected, balancing of the ticket, in the same way that Dukakis selected Lloyd Bentsen, or for that matter, Dubbya chose Cheney.
I don't love the selection of Biden, I don't see him adding much in terms of diversity, I would have rather had Clinton, as I think she represents (for some unknowable reason) an olive branch to blue-collar Democrats and Independents, but then again, so does Biden. It's just I suppose with Biden, Obama avoids the acrimony which built up between he and Clinton, and he avoids Bill's commanding presence at the White House.
But of one thing I am truly certain, the Republicans will SAY ANYTHING at any time, such as the doctoring of climate change data, birth and health statistics, invention of intelligence about Uranium, blaming of North Korea for the acts of Pakistan and Dubai, (this list is endless btw), to them, politics trumps truth, the ends justifies the means, and making a hollow claim (Pawlenty) which is absolutely and easily applicable to their own President, is just fine as long as it gets air time.
And get airtime it will, thanks to Faux News, another certainty - like taxes used to make the rich richer, a certainty you can bet the house on.