Age: 66 going on Time.
Current Position: Senator from Delaware
Former Positions of Importance: None
Pros: You want weight on the ticket? Heft? Credibility? Biden's your guy. Summarizing his credentials as "senator from Delaware" is doing Biden a grave disservice. He has the sixth-longest tenure in the Senate and chairs the Foreign Relations Committee. He's on the Judiciary committee and heads the subcommittee on Crime and Drugs. He played a crucial role in the run-up to the Kosovo conflict of the late 90's.
In short, there are no options out there for Obama who would do more than Biden to add gravitas to the ticket. Biden is a legitimately intelligent man with good ideas and an agile mind. After one of the primary debates his campaign assembled a fairly amusing video containing a couple dozen instances of the various candidates saying some version of "Joe is Right." He could contribute in a big way to an Obama administration.
Oh, and this factor tends to get ignored in these discussions, but should something tragic happen to a President Obama, Biden could assume the office and hit the ground running. Obama would have left the country in good hands. (Obviously that's a macabre thought, but we're talking about the vice president here. "Take over in case something macabre happens" is pretty much the guy's job description)
Biden has a sharp tongue and could handle the attack dog role typically associated with the vice presidential candidate. He rather famously eviscerated Rudy Giuliani in one of the debates, and his takedown of John Ashcroft back in 2004 was quite impressive.
Cons: "Hi, I'm Barack Obama. I earned the trust, love and votes of millions of young people by promising them a change in the stultified culture of Washington D.C. My youthful appearance, impressive oratory and unorthodox biography convinced those voters that I meant what I said about changing Washington and taking the levers of power from the old white men who had been in office for decades.
"And on a completely unrelated note, let me introduce you to my nominee for the office of vice president, Joe Biden! He was in Washington when slaves built the White House and chaired the Senate Foreign Relations Committee back when the gravest threat to our national security were the Barbary Pirates. Hope you don't consider that a disappointment or a betrayal in any way."
There's also a fear that choosing someone like Biden (or Sam Nunn or Chuck Hagel) because of their experience could backfire on Obama. The message you want to send is that an Obama administration would include people who actually know how Washington runs. The message you risk sending is that when the phone rings at 3:00 am in the White House, it'll be Biden and not Obama who handles the crisis. If Biden comes off as more a babysitter than an adviser, Obama will look small and unworthy of the position.
Biden likes to talk. In this era of YouTube, 24 hours news networks and rapid response teams, Biden's admirable willingness to speak his mind and run his mouth is quite refreshing. He doesn't curl up into a ball and spout safe, uncontroversial catchphrases. It's impressive. It's also incredibly dangerous, as Biden himself can tell you. We all remember the "clean, articulate" gaffe he committed on the very day he declared his candidacy. That's a pretty poor way to kick off a campaign.
There's always going to be a fear that some rapscallion with dark hair will heckle Biden at a campaign event and Biden will respond by calling the kid a "dago." That's a good way to lose several newscycles.
Doesn't bring any geographic appeal to the ticket. Delaware's voted for a Democrat in every presidential election since 1992, the rest of the Northeast is solidly in Obama's camp and even if Delaware was in play it only carries three electoral votes.
Verdict: Not the odds-on favorite, but still a solid option. The babysitter dynamic is a tricky problem, but skillful campaigning can send the message that yes, an Obama administration will change things, even if the vice president is an old hand. Regardless, it's unlikely that many of Obama's young supporters will desert him simply because he chose a 66 year old as his running mate. Picking Biden would show how seriously Obama takes the VP's office and how dedicated he is to putting a top-notch intellect in the position.
Biden has also been mentioned as a potential Secretary of State for Obama.