
I personally find this hard to believe - he's only been governor for two and a half years and his foreign policy experience is zero - but with Sen. Jim Webb taking his name out of consideration (he'd rather not go through the vetting process only two years following his 2006 senate run), Kaine would help keep Viriginia in play for the Democratic ticket.
But outside of that Kaine brings nothing to the ticket. Should Obama pick him I would be very surprised.