I favored Castro myself, but she was probably right: Bernie supports this, so it will lose fewer Progressives than it gains Independent votes. She has said she wants somebody who is ready to step into the Oval Office on day one if anything happens to take her out. So she picked a moderate.
Progressives were probably almost all going to vote for her just because of Trump. The real gain a VP can get her is in the Independents, which is now huge. If she can do that, she doesn't need a single moderate Republican vote.
