Democrats are desperate for someone to give them credibility in the Midwest and some Southern States as a VP. If Biden wins the nomination he will place Kamala Harris as VP. Bernie would pick Mayor Pete (if he holds together) as VP.
The “labor oriented southern (well sort of!) Rat to give them credibility” could be Manchin. He’s lately been making some mildly critical centrist statements about the leftward drift of the Rat party. He’s doing this for two reasons:
1. Make himself available to be the Rat “centrist” VP.
2. Position himself better to run for WV Governor.**
** I’ve heard from people who know him that he hates the Senator job!