A MARTÍNEZ, BYLINE: Now that Vice President Kamala Harris looks like she'll be at the top of the Democratic ticket in November's presidential election, the VP spot is wide open. Now, you might have seen some of the memes out there suggesting that she pick a, quote, "straight white man from a swing state" to be her running mate, and that's led to all sorts of speculation about the likes of Governor Josh Shapiro of Pennsylvania and Senator Mark Kelly from Arizona. But how much does the home state of a VP pick actually help in a presidential campaign? Let's ask political scientists Christopher Devine at the University of Dayton and Kyle Kopko at Elizabethtown College. They co-authored the book "Do Running Mates Matter?" Christopher, Kyle, thanks for joining me.
KYLE KOPKO: Thank you.
CHRISTOPHER DEVINE: Thank you for having us, A.
MARTÍNEZ: All right. So if the Harris campaign is thinking about picking a VP candidate to help them carry one of November's swing states, what is your message to them? Kyle, let's start with you there.
KOPKO: Well, first of all, it's probably not going to happen. Whenever we estimate a number of statistical models dating back decades, it's pretty rare that we find a vice presidential candidate that can deliver a battleground state. And even if they could, then it really has to be the decisive state in the Electoral College really to make a difference. So you can think about this as lightning needing to strike ever just right for it to count in the presidential election.
MARTÍNEZ: So, Christopher, the answer to the question the book title poses - do running mates matter? - is apparently, no, right?
DEVINE: They don't matter in the way that we typically think of. So we think of, man, if you pick this person for vice president, people are going to love him or her so much, or maybe they dislike that person so much, that it's really going to directly affect how people vote. Or here's a way to appeal to people from a certain state, as Kyle was speaking to, or that they'll appeal to a certain demographic group. And we just find very little evidence for that. The way that they matter, A, is more in terms of shaping our perceptions of the presidential candidate. What does this pick tell you about who Kamala Harris is, or what does JD Vance tell you about who Donald Trump, at least in a second term, is going to be?
It could tell you something in Harris' case about her political ideology. Also, how good of judgment does she have? And for that matter, we show evidence of this, for example, in 2008, that John McCain's pick of Sarah Palin caused voters to think less of his judgment because they didn't believe that she was ready to be present. They thought it was an irresponsible pick, and so they were less likely to vote for McCain because of that.
MARTÍNEZ: But, Christopher, then, why do you think this idea persists that a VP's home state can help with voters there?
DEVINE: I think it just feels true. There's a lot of things in politics that you hear them so much - there's such a long history of this belief. And by the way, maybe it was more true at some point in the past. It used to be that people had a stronger sense of local identity. They were less likely to move from state to state. And so maybe they actually did value a local or state-based candidate more so than they do now.
MARTÍNEZ: Kyle, so if their home state isn't that important, what attribute should the Harris campaign be looking for in a vice president?
KOPKO: What our data suggests is that voters really value political experience and the ability to serve as president if needed. Now, if we think about the role of vice president, it's a complicated role. Historically, it really hasn't had that much formal power. But in recent decades, we've seen vice presidents playing a much larger role in helping to advance an administration's policy objectives. So I think that those types of characteristics, or the ability for a candidate to engage in that type of work, generally is looked favorably upon by voters.
MARTÍNEZ: What about demographics? I mean, how much does white, Black, woman - how much does that matter now?
DEVINE: We explore this in the book - we call targeted effects, the idea that you could appeal to someone based on a shared identity, whether that's geographic or demographic. And most of the time, what we find is that it's just not there. So I'll give you a couple of examples. It's long been assumed that picking a woman for vice president would bring more votes from women in the election. Geraldine Ferraro was the first woman vice presidential candidate in 1984, and then Sarah Palin in 2008 was the second. In both of those cases, we looked back at the evidence to see is it, in fact, true that women became more likely to vote because of these picks. And we don't find that.
I'll mention one other thing too, and this goes back to kind of the conventional wisdom about VP effects. Everybody knows that Mike Pence helped with evangelicals in 2016, right? Well, what Kyle and I did in our book is we looked at surveys where the same respondents were tracked over the course of the campaign. And so we could see how did they plan to vote before Pence was picked and say, was there a spike in willingness to vote for Donald Trump after he picked Mike Pence? No, we don't find that. So it's another example of how some of these things that seem obvious and they become the conventional wisdom - when you pause and look at the evidence, they don't always pan out.
MARTÍNEZ: Donald Trump has already picked his running mate, JD Vance. And Vance does not necessarily help the Trump campaign in Ohio, his home state. Christopher, can you see any advantages that he brings to Trump's ticket?
DEVINE: The Trump campaign thinks that JD Vance can really appeal to working-class voters and rural voters, kind of these folks who might connect with a message about economic struggle - for that matter, the opioid crisis, given his personal experience in his family and so on. You know, I'm not sure that will work. That's a pretty nuanced effort, but we'll see. I will say that Donald Trump took a risk in picking JD Vance because, based on our evidence, we know that voters value experience. Picking someone who was only sworn into the Senate, his first ever political office, a year and a half ago is a risk. Voters might look at JD Vance and say, hey, maybe this guy has talent. Maybe he'll be ready down the line. But right now, I don't know. And if that's the case, they might question Donald Trump's judgment and hold that against him.
MARTÍNEZ: Kyle, what about the idea that for the campaign - maybe not necessarily for anything else, but just for the campaign - that the vice president can be an attack dog of sorts, kind of defend the ticket and the policies of that ticket?
KOPKO: And that certainly has been a strategy for decades. This is a way that presidential candidates have used a surrogate, a vice presidential candidate, to keep the presidential candidate's hands clean, so to speak. Over time, the vice presidential nominee can get out on the campaign trail, say things that might not sound presidential, and maybe that provides some sort of electoral advantage or boost in certain areas, but also, that's a short-term effect. That maybe will last for a media cycle or two. It's really difficult to say if that has any meaningful long-term effect on a particular campaign.
MARTÍNEZ: That's political scientist Kyle Kopko at Elizabethtown College and Christopher Devine at the University of Dayton. They co-authored the book "Do Running Mates Matter?" My thanks to you both.
KOPKO: Thank you, A.
DEVINE: Thank you, A.
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