So says NR's Michael Graham on the Biden pick, and he has three reasons:

1. Biden puts a grown up on the ticket;
2. Picking Biden shows Obama has grown up, too;
3. Biden knows how to campaign.

It's hard to argue with Graham's reasons, and his explanations. Still, as Graham himself notes:

In the final analysis, I still think Biden will be a net negative, and for two reasons: His choice is a tacit admission by Obama that he's not ready to be president, in the same way that picking Hillary would have been an admission that Obama wasn't strong enough to take on the Clintons. And Biden is a lead-pipe lock to say something on the campaign trail that will cost Obama several days of rosy press coverage.

Readers might not be surprised to know that I think Biden will be a net positive. He might be easy to laugh at, but his presence on the ticket is what matters. And I think that, barring any major gaffes, that's all a lot of voters need to feel comfortable with Obama.