With former President Donald Trump convicted of 34 felony counts in the Manhattan hush money trial, it may seem like the perfect opportunity for President Joe Biden to regain control over the election narrative and take the lead in polling. After all, voting for a literal convicted felon seems very much like a bridge too far for the few persuadable voters that remain in this election.
However, as FiveThirtyEight’s Nathaniel Rakich points out in his article, while the limited polling we have for a hypothetical Trump conviction shows Biden leading by a good amount, his share of the vote is statistically unchanged. In fact, almost all of Trump’s lost support is transferred to “unsure/someone else,” suggesting that these voters are simply not sold on voting for Biden, even if his opponent has been convicted of numerous crimes. Despite receiving 51% of the vote in 2020, President Biden’s standing in the polls seem hopelessly stuck in the low-40s, with little sign of breaking through anytime soon.
This brings us to a greatly underappreciated statistic when it comes to presidents running for reelection: their approval rating. Although it hasn’t come up as frequently in this year’s presidential election discourse, a president’s approval rating on election night is actually one of the best predictive measurements of the president’s share in the national popular vote. In the table below, I’ve assembled the election night approval ratings for every president running for reelection since Richard Nixon in 1972 (courtesy of FiveThirtyEight), and compared that number to their reelection vote share:
| President (Election Year) | Election Night Approval | Final Vote Share | Difference in Share |
| Nixon (1972) | 61.3% | 60.7% | -0.6% |
| Ford (1976) | 44.5% | 48.0% | 3.5% |
| Carter (1980) | 36.9% | 41.0% | 4.1% |
| Reagan (1984) | 57.7% | 58.8% | 1.1% |
| Bush (1992) | 33.9% | 37.4% | 3.5% |
| Clinton (1996) | 56.3% | 49.2% | -7.1% |
| Bush (2004) | 47.8% | 50.7% | 2.9% |
| Obama (2012) | 50.5% | 51.0% | 0.5% |
| Trump (2020) | 44.5% | 46.8% | 2.3% |
As you can see, presidents are mostly able to overperform their approval rating, but by relatively slim percentages usually ranging from 1-4%. The big outlier in this table is Clinton’s 1996 reelection, where his “underwhelming” reelection vote share may have been an artifact of Ross Perot’s third party candidacy and overly rosy polling for Clinton at the time.
This brings us to the 2024 election campaign. As of this writing, Joe Biden is polling at 39.5% in the FiveThirtyEight national polling average, as the same website measures his approval rating measured to be 37.8%. In the Hill/DDHQ aggregates, Biden’s vote share is a similar 39.7% while his approval is measured at 40.2%. Biden does noticeably better in the two-way polling average, increasing his share to 44.3% in the Hill/DDHQ polling average. But in either case, Biden is unable to “break through” the typical threshold of overperformance for an incumbent President (1-4%) relative to his approval rating, and as stated above, hypothetical conviction polls currently show little potential boost to his vote share.
Thus, we have reached what I’m referring to an “approval ceiling” for Biden. As the presidential election is a choice between two candidates and not a pure referendum on the incumbent, the president is able sway a few disapproving voters to their side in every election, but asking a large amount of a disapproving electorate to vote for you, even if your opponent is a poor one, is still a very uphill task. While Trump may prove to be such a poor candidate that Biden escapes political gravity to overperform his eventual approval rating by five, six, or even seven percent, it may mean little if his approval rating is so low that he is unable to win the election anyways (in fact, he would only receive ~48% of the vote if he overperformed his current approval rating by 10%).
As post-conviction polling is released in the next month, pay attention to not only a potential Biden rebound in the margin—but also how his approval rating correlates to his new polling share.