Two weeks since the Trump-Biden debate, a lot of post-debate polling of the presidential contest is now available. The good news for Team Biden is that the polling collapse many Democrats feared following the president’s poor debate performance has not occurred. But there has been some erosion, generally speaking, in Biden’s support. And without question, polls reflect high and significantly increased concerns about the president’s age and fitness for a second term, even within his own base. The biggest question in interpreting these polls is about one’s prior assumptions: If you believe Biden was already losing badly and needed a bounce from the debate, its impact could be described as calamitous. Otherwise, the polling continues to show a close race that isn’t out of reach for the incumbent and wasn’t significantly changed by the debate.
Before delving into the numbers, I want to mention a methodological decision: Henceforth, we will rely mostly on polling averages from FiveThirtyEight rather than RealClearPolitics, thanks to the latter outlet’s stubborn inclusion of dubious polls (e.g., Rasmussen and the various Harris variations) that tend to put a thumb on the scales for the GOP. Credible polling averages are now also regularly published by the Cook Political Report, the New York Times, and the Washington Post, but at present, FiveThirtyEight’s averages are the most comprehensive and accessible. For one thing, FiveThirtyEight seeks to grapple with support for non-major-party candidates rather than simply disregarding it, like the Post and Cook have chosen to do.
According to FiveThirtyEight, Trump’s national lead has grown from 0.2 percent (41.1 percent to Biden’s 40.9 percent) on the day of the Atlanta debate to 2.1 percent (42.3 percent to 40.2 percent) right now. In the seven battleground states, the trend lines also show modest erosion for Biden, with the crucial psychological difference that Trump leads in all of them now. In Arizona, Trump led by 3.8 percent the day of the debate and leads by 4.4 percent now. In Nevada, Trump’s lead grew from 2.7 percent pre-debate to 4.8 percent now. In Georgia, Trump actually lost a tenth of a percent since the debate but still leads by 5.2 percent. In North Carolina, Trump’s lead is steady at 6.0 the day of the debate and 6.1 percent now. In Michigan, Biden was up for an entire week before the debate but is now trailing by 0.5 percent. And in Pennsylvania, Trump’s lead grew from 0.5 percent on June 27 to 3.3 percent now.
A few other post-debate state polls have drawn some attention, notably a St. Anselm poll of New Hampshire showing Trump up 2 percent in a state Biden won by seven points in 2020. An expanding map of battleground states isn’t good for the candidate trailing in so many of them. More strikingly, internal poll findings indicate negative perceptions of the president’s fitness for office. A new Pew post-debate survey shows the percentage of Biden supporters adjudging him as “mentally sharp” has declined from 82 percent in October of 2020 to 53 percent now. Worst yet, a shocking 71 percent of Biden supporters say they wish both major-party candidates would be removed from the ballot. An Economist–YouGov post-debate survey showed 46 percent of Democrats either “definitely” or “probably” think Biden should “step aside” from the nomination, as opposed to 41 percent who “definitely” or “probably” do not. That’s in a poll that gave Trump a narrow three-point lead in the race.
It’s reasonably clear that if Democrats do push Biden into stepping aside, it’s not the post-debate polling trends that are responsible but rather a set of assumptions about where Biden was before the debate and how far he needs to go now. Many Democrats are transfixed by the fact that Biden barely won the Electoral College in 2020 while winning the national popular vote by 4.5 percent. If he needs a similar margin to win in 2024, then he’s in big trouble. It has been frequently noted that Democratic nominees had robust polling leads at this point in every presidential cycle since 2000. In both 2016 and 2020, Trump’s support was generally underestimated by the polls. Combining all these often-unstated assumptions, some Democrats think Biden is farther behind than the numbers show, needs to be well ahead, and has the makings of a future collapse in support.
Biden defenders are more likely to focus on his narrow but still visible path to 270 electoral votes (based on sweeping Michigan, Pennsylvania, and Wisconsin, states where he’s still doing relatively well after the debate), while arguing that changes in the composition of Biden and Trump’s bases of support make the Republican dangerously dependent on voters who may not turn out. From that point of view, Biden doesn’t need a national popular-vote win and is within striking distance of victory right now.
So some Democrats interpret Biden’s poll standing as showing his glass is nearly empty and getting emptier every day. Given the terror that many Democrats experience at the thought of a second Trump administration, that can make any donkey jumpy.
