The Veepstakes
A mathematician’s thoughts on a political and historical problem

It appears very likely that either Joe Biden or Bernie Sanders will be the next Democratic presidential nominee. Actuarial tables suggest that if either is inaugurated, they have about a 1 in 6 chance of dying by the end of their first term in office; in addition to death, incapacity or disability is also a major concern.
The stakes attached to the vice presidency have never been this obviously high. My advice would be caution: The most important role of the vice presidential nominee is to step into the presidential nominees’ shoes. Trust that voters understand that.
Choosing a running mate in order to appease a disgruntled political faction — either a different faction of the same political party, or voters outside of the political party — has little positive electoral impact. It may even have a negative impact, as voters do not trust politicians who are clearly pandering insincerely. It’s also reckless.
The vice president on the campaign trail
Selecting the right running mate for the campaign trail drives a lot of vice presidential selections. The factors that go into deciding what vice president will help win votes can be divided into three categories.
The first category is that the vice president is expected to do a good job as vice president: Vice presidents assist the president. They are supposed to preside over the Senate, expected to advise the president, and serve as a president’s proxy.
The other two categories are purely politically strategic reasons. Vice presidents have been chosen to try to win over swing voters in the area the vice president is from or to placate a rival political faction. There is little if any evidence showing that this works.
Trying to win over swing voters
The Electoral College system is a chaotic mess of a system, and close presidential elections depend on narrow margins of victory in key battleground states. Some running mates are chosen to help put a key state into play, or to shore up the party’s performance in a region where the nominee is less popular. Most early presidential tickets paired a southerner and northerner on this theory.

While there is some evidence in favor of a home state advantage, there is limited evidence that geographic balance helps a presidential ticket. Even the home state advantage is of fairly questionable strength.
For example, John Edwards didn’t carry North Carolina for John Kerry in 2004, even though the next Democratic ticket (Obama/Biden) won it in 2008. Paul Ryan didn’t carry Wisconsin for Mitt Romney in 2012, though the next Republican ticket (Trump/Pence) won it in 2016.
Appeasing a rival faction
In some cases, vice presidents are chosen from a rival political faction, as a matter of apparent political expedience. It’s not clear that symbolically picking a rival as vice president helps win votes. However, it is clearly reckless.
In two notorious cases, the vice president has come from a different political party; Thomas Jefferson and Andrew Johnson. Thomas Jefferson caused trouble for the Adams administration, although John Adams did not choose Thomas Jefferson as his vice president. The 1796 election was complicated, so that’s another topic for another time.

Even drawing a vice president from a rival faction of one’s own political party is risk, however. In 1840, John Tyler was chosen as the running mate of William Henry Harrison in order to appease southern Whigs. It’s possible that this helped win votes in Southern states; however, as I mentioned, there is little evidence overall for a “home region” effect in recent presidential elections. Harrison died shortly after being taking office. The Tyler presidency went poorly, and he was not nominated for re-election.
In 1848, the northern Whigs had split into two faction, the Cotton Whigs and Conscience Whigs. Cotton Whigs aligned with southern Whigs to nominate Zachary Taylor for president; however, in order to appease Conscience Whigs, the party nominated Millard Fillmore for vice president. When Zachary Taylor died, Fillmore’s break with his predecessor’s administration was one of the most complete in history, with Taylor’s entire Cabinet leaving immediately.
In 1864, Andrew Johnson was added to Abraham Lincoln’s ticket in order to appeal to War Democrats. This was part of a complicated bit of political calculus that involved trying to rein in a rival wing of the Republican Party. Lincoln was re-elected by a wide margin, partly due to the fact that the Confederate states didn’t participate in the election.

In 1865, Lincoln became the first president to be assassinated, and the second to die in office. The politically strategic choice of Andrew Johnson had significant negative consequences at this point. After succeeding to the presidency, President Johnson attempted to obstruct Reconstruction and became the first president to be impeached. He narrowly avoided removal from office, but was not nominated for re-election.
In 1880, Chester A. Arthur was added to James Garfield’s ticket in order to appease the disgruntled Stalwart faction of the party. Garfield was then assassinated by a deranged Stalwart who proclaimed his intention was to make Arthur president. Arthur was not nominated for re-election; in poor health himself, he died in 1886.

Arthur was the fourth vice president to step into the shoes of a deceased president. Each of the first four accidental presidents was chosen to appease a rival political faction, with reckless disregard for how they might perform as replacement presidents.
A vice president from a rival faction provides a clear political motive for assassinating the president. While there is no direct evidence that Lincoln’s assassin wanted to make Johnson president, Garfield’s assassin admitted it openly. Choosing a vice president from a rival faction is reckless even when the presidential nominee is young and healthy.
Nominating an ally for vice president
If we consider the last seven elections, there’s very little reason to think that it’s harmful for a presidential nominee to choose a vice president closely aligned with their own politics and personality. To the contrary, the most successful presidents in the last thirty years all did exactly that.

In 1992, Governor Bill Clinton of Arkansas bucked conventional ticket-balancing wisdom by choosing Senator Al Gore from neighboring Tennesee, whose political resume looked very similar — a fellow young moderate Southerner. The Clinton-Gore ticket won more electoral votes than any other ticket from 1992 to 2016.
In 2000, Governor George W. Bush of Texas bucked conventional ticket-balancing wisdom by nominating fellow Texas oilman Dick Cheney. Since the Electoral College bans voters from casting two ballots for residents of their own state, this meant that Dick Cheney had to change his legal residence to Wyoming. The Bush-Cheney ticket won a greater share of the vote than any other Republican ticket from 1992 to 2016.
In 2008, Senator Barack Obama picked a fellow senator — Joe Biden. Both were fairly close to the center of the party politically. Biden’s main qualifications were that he had experience that Obama lacked and had good personal chemistry with Obama. The Obama-Biden ticket won a greater share of the popular vote than any other ticket from 1992 to 2016.
Who should the nominee pick for vice president?
So. Let’s review the facts. It’s possible that a vice presidential nominee could help win their home state, although this didn’t happen with the last two presidential nominees from potential battleground states (i.e., John Edwards in 2004 and Paul Ryan in 2012).
It’s otherwise unlikely that a strategic or symbolic choice of vice presidential candidate will help a candidate in a region or help win over voters who prefer the vice presidential nominee to the presidential nominee. I can just as easily argue that voters will be reassured by knowing that the vice president is fully in the president’s camp — and therefore know what to expect from the presidency, even if the nominee’s health fails.
However, regardless of any uncertain electoral effects, what is certain is that choosing a vice president in order to symbolically appease a political faction is reckless. This is true whoever the nominee is, but especially if the nominee is a decade older than William Henry Harrison was.
So what does that mean? Nominees for president should pick someone they can trust to advance their agenda, fulfill their vision, and that they trust deeply enough to put them a heartbeat away from the president. For Biden and Sanders, this does not mean choosing someone who differs significantly on major policy issues or who attacked them during the primary.