Barack Obama made the boring, but safe, choice. One senses that Joe Biden will not violate the first and only rule of running mates: do no harm. He has run for president twice and served in the Senate for longer than I have been alive. He's been there, and he's been vetted. He won't appear as a deer in the headlights and there won't be any revelations about him undergoing electro-shock therapy. Biden has the unique ability to play the attack dog without becoming a devil figure among political adversaries. If Bill Clinton was born to be president, Joe Biden was born to be vice president. To quote that black-robed sage of the fairway Judge Smails, "The world needs ditch diggers, too."

Good work on the prediction, however I disagree with one thing you've written: that Biden is a safe choice. Chris Cillizza has written a good article detailing some of the potential problems with Biden. Biden is a loose cannon, and is slightly wacky.

Also, I think Biden may point out the glaringly obvious about Obama to voters who haven't been paying attention. Obama just doesn't have the experience that most voters expect in a presidential candidate. There wasn't really any way to avoid that, however. Just about anyone Obama could have picked would've had more experience than he.

Link to Cillizza article: http://blog.washingtonpost.com/thefix/