Joe Biden’s decision to end his campaign and endorse Kamala Harris has upended the presidential race. But from one vantage point, it was a perfectly understandable decision.
Even before the debate that catalyzed concerns about his candidacy, he faced an uphill battle. As we wrote back in March, his approval rating of 38% put him on track to win 48% of the two-party vote. Biden could only hope that, like some other presidents, his approval would increase in the election.
In turn, that depended on Biden’s ability to win over what we described as “low-hanging Democratic fruit.” In March, his approval rating among Democrats at the time was around 80%, lower than Trump’s at this point in 2020. Similarly, Biden was winning 83% of his 2020 voters in a March New York Times poll while Trump was winning 97% of his previous supporters.
There was reason to think that Democratic fence-sitters and potential defectors would return to the fold, as campaigns tend to rally partisans to their party’s candidate. Biden experienced such a rally in 2020, as his favorability rating among Democrats increased by almost 20 points.
But over the past six months, the opposite happened. President Biden grew more unpopular among Democrats:
The graph shows the net favorability rating – the percent with a favorable view minus the percent with an unfavorable view – of Biden and Trump among members of their own party. In January, both had a rating of about +70, according to polling by the firm Civiqs.
Since then, the trend for Trump fits the pattern of “partisan activation” in which presidential nominees become increasingly popular within their own party. By last week, Trump’s net favorability among Republicans had increased to 78.
Biden’s net favorability rating among Democrats, however, moved in the opposite direction – dropping from +69 in January to the mid-60s by June. His standing dropped into the +50s after his debate performance.
The same trend is evident in other polls. For example, although Biden had more support from Democrats surveyed in YouGov-Economist weekly tracking polls, that support still decreased after the debate. In YouGov’s three weekly polls before the debate, an average of 83% of Democrats rated Biden favorably. In the 3 polls since the debate, 79% of Democrats did. Meanwhile, the percent of Republicans who viewed Trump favorably increased from 85% to 88%.
Biden was already less popular among voters from his own party than any president running for reelection since George H.W. Bush lost his reelection bid in 1992. That is a crucial weakness in a polarized electorate, which makes mobilizing base voters important to winning national elections.
Biden’s debate debacle further weakened this already tenuous position with Democratic voters. That effectively ended his viability as the party’s presidential nominee.
