What do you want in a running mate?
Some of the things that have gone into the decision in the past include regional balance or ideological balance, but there have also been cases of doubling down on perceived strengths. Sometimes you want an attack dog. During the primaries, everyone always talks about the top two candidates teaming up, but that rarely happens (Kerry/Edwards is really the only recent example).
People need to feel that the running mate fills the most important role of a Vice President: ready to be President in a crisis. Everything else pales compared to this.
Only in desperation have candidates picked a history-making choice such as first woman. John McCain and Walter Mondale both faced uphill climbs and rolled this dice picking a woman to try and give some extra mojo to their campaigns. McCain’s pick may have cost him the presidency, though he still lost by a lot. It’s hard to tell if anything made a difference for Mondale.
But in both of those cases, the risk was run of taking the focus off the top of the ticket. Lloyd Bentsen polled stronger than Michael Dukakis after his debate performance against Dan Quayle. Ferraro was more interesting to follow than Mondale who was always going to be blown out.
Someone who understood these dynamics well was Barack Obama. He understood that his role in history as the first black president was a story. He tried not to make it the story, but no matter what he or his campaign did, that was always going to be a factor. A little revolution is usually enough for most people. Perhaps the best reason not to bring Hillary Clinton in as Obama’s running mate in 2008 was that it would have drained energy from the top of the ticket and done little to make people feel comfortable about relative inexperience, since, standing on her own two feet, Hillary only had four years more of Senate experience. Joe Biden, on the other hand, brought decades of experience.
And let’s be honest. A white man next to Obama actually right-sized his narrative instead of making it all about race or identity politics in a way that primary voters don’t want to acknowledge but that in an election where you need some nervous Republicans to cross over to get the result you want might be indicated.
So, even if I thought Julian Castro and Tom Perez were qualified to be president, and I don’t think they are, I would say first that the story needs to be about the history-making aspect of Hillary, not her running mate. Second, more cynically, I would say is there really anything that can be done to bolster Latino turnout this election that Donald Trump doesn’t already provide? Also, Perez and Castro speak terrible Spanish.
I also don’t believe in ideological balance. Any daylight between the candidates becomes a story, just as it would when they’re in office. Elizabeth Warren also has very thin chops to claim being ready for the nuclear codes. Remember, we’re going to try and emphasize the risks of putting a rookie like Trump in charge. A first-term senator doesn’t bolster this argument no matter what anyone says or how smart her policies are. This is also why I wouldn’t want Sherrod Brown. I don’t believe that regional balance is a factor anymore. Brown wouldn’t be a decisive factor in delivering Ohio.
Two who are qualified to be president are Xavier Becerra and Tim Kaine. Kaine has been a governor and speaks actual fluent Spanish. He’s a boring old white man. He’s qualified to be President. He won’t steal the spotlight. If you really think running mates can deliver states, Virginia is almost as good to have as Ohio. Becerra would take some of the spotlight off of Hillary because he’s not a national figure, isn’t a senator or governor and therefore might be seen as a pick based on his demographics.
So, by process of elimination of all of those rumored to be on the list, I would most strongly support Tim Kaine and very much be against Castro. Everyone else falls in the middle.