In recent months there has been much discussion about President Biden’s approval ratings and how Americans are feeling. It is therefore not surprising that many media commentators have rushed to speculate about the possibility of a Trump victory in 2024.
Let’s first acknowledge some obvious caveats to keep in mind.
First, a substantial portion of Biden’s lagging approval is coming from within his own party: since 2022, between 20-30% have not approved of Biden. The current crisis in the Middle East, which has put President Biden in a difficult position, has likely allowed this disapproval to harden even further. But on Election Day, these dissatisfied Democrats—and many Independents as well—will likely look at Biden differently when the prospect of another Trump presidency is looming large.
A second fairly obvious caveat is that, with inflation changing a great deal over the past 2 years, Americans’ sentiments about the economy have changed quite dramatically, which can only help Biden’s chances going forward.
But an even more fundamental caveat exists, and it is one that is surprisingly overlooked. Simply put, the fact that Biden has been in office for one term matters. A lot.
History Repeating? The Case of 2012
In September of 2011, then-President Barack Obama was struggling. His approval was virtually identical to Biden’s current approval rating. Views of the economy were negative and polls found Obama trailing to one of the then-front-running Republican contenders, Mitt Romney. On the eve of the 2012 election, at least some polls had Romney narrowly leading Obama.
It seemed clear that Americans were ready for a change.
But change is not what happened. Obama handily won the two-party vote share (that is, the total number of votes won by the Democratic and Republican Party candidates) by about 4 percentage points.
Given political scientists’ findings on U.S. presidential elections, no one should have been surprised by this outcome. Why? Because in November of 2012 Obama was the incumbent president, just as Biden will be in November of 2024.
The Power of Incumbency
Every presidential election seems unique, but the data doesn’t lie. My recent paper, conditionally accepted at the peer-reviewed journal, Political Science Research & Methods, looks at all presidential elections since 1952. Despite all the different candidates, national priorities, international challenges, economic conditions, etc. over the past 72 years, incumbent candidates have won the popular vote a remarkable 78% of the time.
These incumbent candidates have averaged 54.5% of the two-party vote share—a massive 9 percentage-point average advantage over their non-incumbent challengers.
Even if we go back to the first election following the end of the Civil War (1868), the results tell us the same story: incumbent presidents average well over 50% of the two-party vote share.
This is not to say that incumbency is the only thing that matters. After all, 2020 saw the incumbent lose the popular vote by 4 percentage points. But given the historic unusualness of that election (the Covid-19 pandemic, skyrocketing unemployment, unprecedented controversies surrounding Trump, etc.), 2020 may be better viewed as an exception that proves the rule.
Indeed, the 2020 and 1980 elections are the only two exceptions to the rule of incumbent victory since 1952 (excluding Bush Sr. in 1992 which, though only his first term, was the Republican Party’s third term in office). The lesson is clear: while it is not quite a “guarantee,” incumbency confers an unequivocal advantage.
Isolating Incumbency’s Effect
Political scientists have written extensively about the power of incumbency when using statistical analyses to forecast election results. Indeed, aside from the economy, it is one of the most consistently powerful predictors of election outcomes.
But why should it matter?
There are many potential reasons, but my recent experiment—which also employed an online experiment featuring several thousand participants—shows that a majority of citizens (Democrats, Independents, and Republicans alike) simply believe that incumbents should generally be elected for a second term. In short, a president serving only one term (when legally allowed to serve two) just doesn’t seem to sit right with many Americans.
Existence of such a norm in U.S. politics has a huge implication: simply knowing that a candidate is an incumbent should be enough to nudge a substantial share of voters toward voting for that candidate.
Indeed, by isolating candidates’ incumbency status from all other considerations (name recognition, the economy, etc.), this is precisely what my experiment found. Compared to when their incumbency status is not specified, candidates who are identified as the sitting president—whether Democratic or Republican—see an increase of 5.6 percentage-points in vote share. By the standards of modern presidential elections, that is an absolutely game-changing bump.
The Months Ahead
Of course, each election comes with unique features. The potential candidacy of third-party candidate, Robert F. Kennedy Jr., for example, may disproportionately erode some of Biden’s vote share. Developments in the Middle East, whether the Electoral College system changes, and the likelihood that Congress takes actions to curb inflationary pressures, for example, all introduce a healthy amount of uncertainty into what will happen in November.
It is also worth noting that Trump is a (former) president who served only one term, meaning that some share of voters may feel he therefore deserves a second term. In short, might some voters see Trump, rather than Biden, as the real incumbent in 2024?
While this is of course possible, we simply don’t have enough evidence to assume that many voters will think this way come November (the last time sitting president lost reelection and then ran again (and won) was 1892).
Thus, to the extent voters see Biden as the true incumbent, he is likely to benefit from incumbency advantage. Indeed, a poll from this week finds that Trump’s polling advantage over Biden—an advantage we have heard so much about in recent months—is narrowing. Other analyses now shows a small, but growing, Biden advantage.
Again, this is not at all to say that Biden’s incumbency guarantees a 2024 win. (There are no such guarantees in U.S. politics.) Rather, it is to say that, statistically, a Biden loss in 2024 would be very strange. Thus, absent some very strange circumstances (for example, as there were during the 2020 election), history implies a clear advantage for Biden.
In sum, presidential elections do not ask voters whether they like the sitting president. Instead, they ask voters whether they prefer the sitting president over the president’s opponent. Failure to appreciate this difference leads pundits to regularly predict incumbents’ political doom, despite how often incumbent presidents have won reelection over the past 150 years, and despite the intrinsic power that incumbency appears to hold.
To be sure, Biden has weaknesses. So did Obama in 2012. But the asset they shared—incumbency—should not be overlooked. Media’s focus on Biden’s weaknesses might be good for getting clicks, but it ignores his crucial strength.