2020 is shaping up to be a big year for the two things I love writing most about at The Postrider: the United States Senate, and the vice presidency. And we’re going to have a swath of content featuring both of these items unveiled over the course of the coming election year. We’ve held off a little bit this year to give you some sense of relief from the seemingly endless campaign, so it might shock you to know that we’re jumping the gun to start looking – in broad terms – at who the Democratic vice presidential nominee might be.

There’s scant evidence to suggest that a vice presidential running mate makes a difference in the general election. They may provide a slim bump in the polls if they’re from a certain state, but notable “swing state” picks like Paul Ryan (Wisconsin), John Edwards (North Carolina), Lloyd Bentsten (Texas), and Geraldine Ferraro (New York) all lost their home state; in fact, Tim Kaine (Virginia) and Al Gore (Tennessee) are the only two running mates from swing states since 1976 to have won their home states.1We’re using the same standard as this NPR article, which describes a swing state as any state that had a margin of <5% between the two candidates in any of the four elections chronologically closest (before or after) a particular election year, as well as the election itself. Mike Pence (Indiana), for example, is not a swing state pick, even though there was one election (2008) in which it was won by a margin of less than five percent. Yes, I too find it humorous to think of a time that Tennessee, Texas, and New York were all once swing states, but rejoice in the fluidity of the American electoral system.  Picking someone from a different region and with different political experience than the presidential nominee seems to be a consistent choice by campaigns, though it’s unclear whether or not this actually matters come election day. Nonetheless, for those following campaigns and politics at large, considering potential running mates is high entertainment.

We’ll be unveiling a VP tracker in the next few months to put metrics and actual hard evidence into our analysis of who is likely to be a VP pick for each potential presidential nominee. Over the course of background research for that tracker, I had to face a key question: have we already met the VP candidate? By this I mean, did they run – or are they still running – for president? The Democratic field has had 27 “major” candidates,2We’re relying on the New York Times definition of “major”. with a possible 28th soon to come, a massive number that’s unprecedented in modern presidential campaigns. Many of these names came and went, despite having held prominent offices, and it begs the question if we’ll see one of them eventually resurface as the running mate of an eventual candidate Warren, Biden, Sanders or whoever you believe will grace the DNC stage that fateful night in July.

The easiest way to do this was just to look back at the historical record. I looked at every primary since 1976 that had no incumbent president on the ticket, compared the total number of candidates (this time using FiveThirtyEight’s metric for “noteworthy” candidate, which errs towards over-inclusivity), and looked at how many races featured a running mate who also ran in the primary:

 This is a very small dataset, not enough to do any real statistical analysis, but there are a couple of takeaways that illustrate what to expect of the soon-to-be-nominee picking a running mate in mid-2020:

Choosing a “has-ran” is not as common as you’d think

Considering the media attention you earn by launching a presidential run and the intense focus on the dynamics between candidates, debates, and policies throughout the primary, it’s actually surprisingly rare for the running mate to be chosen from amongst those who ran in the primary. It’s only happened in three of these 15 primaries since 1976. The reason for this is likely tied to political baggage. It’s probably easier to start fresh once you’re the nominee and reset the campaign cycle entirely with someone who has not had attack ad after attack ad run against them. You don’t want the contrasts and contradictions that emerged during the primary between you and your running mate to be focused on or unpacked; projecting unity and a compelling ticket needs to be the emphasis.

It appears to peak in a mid-sized primary

Primaries that are smaller than the average (10.07 candidates) and primaries that are larger than the average do not historically lead to an also-ran candidate being selected as a running mate. That makes sense for primaries that are small, because it means there are fewer candidates who could potentially be considered, but is interesting for famously large fields (like the 1976 Democratic primary or the 2012 or 2016 Republican primaries). In fact it only appears in this sample that those at almost exactly the average (around nine to eleven candidates) saw a running mate selected from the primary field.

Gold years depict those in which the vice presidential candidate also ran in the primary

Initially I thought this might have something to do with the competitiveness of the primary, how those with more than eleven candidates appear to be less competitive, and those with a small slate would also be less competitive, but the data was inconsistent. The average “competitiveness” (which I took in a loose measure to be the distance between the percentage of the vote that the most-vote-receiving candidate and the second-most-vote-receiving candidate received) was the winning candidate ahead by over 27%. However, both the 2004 Democratic primary and 1980 Republican primary (both in which a running mate was chosen from the other candidates in the primary) were 42% and 36% respectively. Only the 2008 primary, in which Barack Obama chose Joe Biden as his running mate, was the competitiveness extremely high (actually negative 0.7%, as Hillary Clinton received more votes overall). Of all the primaries where a running mate had not also run, they were across the board in terms of levels of competitiveness, ranging from the 2000 Democratic primary, where Al Gore was ahead of second-place Bill Bradley by more than 54% but chose Joe Lieberman (who did not run in the primary) to the 1984 Democratic primary where Walter Mondale beat out Gary Hart by just 2.4% but selected Geraldine Ferraro (who also did not run in the primary). 

Competitiveness does not seem to be the determining factor, the reason it has only happened in mid-sized fields is probably a statistical fluke. As noted, there are not enough samples to justify making a conclusion.   

The current field may be too big to warrant historical comparison

This being said, the current Democratic primary field has had 26 candidates so far, across a fairly wide spectrum of positions, ideologies, and demographics. The argument for things being a bit different this time is that at some point you’re running out of great picks elsewhere if every up and coming politician is already in the field. Granted, 27 candidates is not that point; I would estimate that the “long list” for any potential Democratic nominee would include around 50 candidates, and that there’s probably a fairly large amount of overlap in those picks between the candidates still in the running for the nomination. There are plenty of Democratic senators, representatives, governors, military leaders, former cabinet secretaries, and other notable party figures or celebrities that are likely to be considered. But the truth is that of those 50 or so, roughly 20 of them have probably already jumped in the presidential race.

If I were to venture a guess, I would still surmise that the eventual Democratic nominee will choose someone who was not in the Democratic primary; as that historically happens about 80% of the time, and this primary has already had some vitriolic moments between the candidates. Even those candidates who we might assume to be angling for the VP slot on a future ticket if they do not win the nomination have gone out of their way to attack the frontrunners. Picking someone without a history of attacking you on the campaign trail and with a solid complementary record seems to be the right move in such a crowded year.