From CBS:

A: Well, you know, I think it’s premature. You won’t see me as a vice presidential candidate — you know, I’m running for president. We have won twice as many states as Senator Clinton, and have a higher popular vote, and I think we can maintain our delegate count — but you know, what I’m really focused on right now, because all that stuff is premature, is winning this nomination and changing the country. And I think that’s what people here are concerned about. How are you going to provide health care to every American? So I spend a lot of time talking about the plan I wanted to put in place that would not only lower costs for those who already have health insurance, but also make sure people who don’t have health insurance can get health care as good as the health care I have as a member of Congress. Those are the kinds of issues that really make a difference in people’s lives, and we’re going to keep on talking about them.

My take? If it works the other way and the slot is open, you take it. You take second base when you are facing the outfield and a VP slot if it is in the vein of Al Gore would give Obama the credentials he is currently lacking when it is his time in the future. Seriously, you take the position it is much easier to run for the White House when you are already spending most of your time there.