http://www.politico.com/story/2016/07/tim-kaine-takeaways-226059
It was always going to be Kaine.
People close to Clinton were telling me, as early as February, that there really wasn’t anyone else on their short list. The main reason Clinton chose Kaine is so simple as to be unbelievable:
She thinks he could serve as president if she can’t, and didn’t think anyone else she talked to fit that criterion.
He speaks Spanish pretty fluently (a vestige of his work in Honduras) and has been a member of a black Catholic church in Richmond for decades.