The Debate Hurt Biden, but the Real Shift Has Been Happening for Years

In the wake of the first presidential debate, a chorus of top Biden allies and campaign officials has advanced a simple message: The race has not fundamentally changed.

In a sense, they’re right.

Far from upending the contest, the latest New York Times/Siena College poll on Wednesday finds that the debate reinforced the central dynamic of the election: the political decline of President Biden, who no longer possesses the advantages that allowed him to defeat Donald J. Trump four years ago.

Overall, the poll finds Mr. Trump leading Mr. Biden by six percentage points among likely voters and nine points among registered voters nationwide. In each case, it’s a three-point shift toward Mr. Trump since the last Times/Siena survey, taken immediately before the debate.

Historically, a three-point shift after the first debate isn’t unusual. In fact, it’s the norm. Over the last seven presidential elections, the person generally considered the winner of the first presidential debate has gained an average of three points in post-debate polls. Sometimes, the shift lasts; other times, it fades. But either way, debates don’t usually fundamentally change a race.

In terms of the polling, this debate is not an exception — at least not yet. The debate may ultimately prove to be the breaking point for Democratic politicians considering whether to stand by Mr. Biden, but the poll doesn’t show that the debate completely upended public opinion about the candidates. Instead, the debate exacerbated Mr. Biden’s political liabilities, which had already imperiled his re-election chances.

Four years ago, it was the absence of any major political liabilities that allowed Mr. Biden to prevail over Mr. Trump. He won the Democratic nomination and ultimately the presidency because he was a well-liked, relatively moderate, broadly acceptable candidate who could unite the politically diverse voters who disliked Mr. Trump. At the time, polls showed that a majority of voters had a favorable view of Mr. Biden. It was just enough for him to narrowly prevail in the Electoral College — by less than one percentage point across deciding battleground states.

Mr. Biden is not a broadly acceptable candidate anymore, the polling shows, and as a consequence he no longer leads Mr. Trump. Long before the debate, his approval and favorability ratings plunged deep into the danger zone for an incumbent. More ominously, his numbers were falling even though the conditions for a Biden comeback always seemed to be around the corner. Inflation was subsiding. The general election was heating up. On paper, an incumbent should have been the favorite — and his opponent was a candidate accused of multiple crimes, and recently convicted of a felony.

But today, his approval rating stands nearly a net 10 points lower than it was ahead of the 2022 midterm election, when inflation was over 7 percent. With the economy and consumer confidence improved since then, perhaps the best remaining explanation for this steady erosion is growing concern about his age.

By every measure, the poll finds that the debate took yet another toll on the public’s already diminished view of him. His favorability rating fell two points after the debate, to 36 percent from 38 percent before the debate. By contrast, it was 52 percent in the final Times/Siena poll before the 2020 election.

The share of voters who said Mr. Biden is “just too old to be an effective president” rose five points, to 74 percent from 69 percent pre-debate. Only 36 percent said Mr. Biden was too old in June 2020.

These modest shifts after a debate aren’t necessarily significant in the grand scheme of things. It’s certainly not a “fundamental” change. What is fundamental is a 15- or 30-point shift over four years. While Mr. Biden sometimes performs better than he did last week, the long-term trend suggests that the accumulated effect of countless interviews, speeches, photographs and social media posts has left much of the public with the impression that he is no longer as well equipped to serve as president.

For much of the cycle, the optimistic case for Mr. Biden rested on the assumption that voters would increasingly focus on Mr. Trump’s shortcomings once the campaign intensified. In this view, disengaged voters would tune in and vote on democracy and abortion, as many did in the midterm election.

Indeed, Mr. Trump remains just as unpopular as he was four years ago. In fact, the share of voters with a favorable view of Mr. Trump is almost exactly the same after the debate (43 percent among likely voters) as it has been in Times/Siena polls so far this year (44 percent); and as it was ahead of the midterms (43 percent); or as it was before the 2020 presidential election (44 percent).

But in last week’s debate, Mr. Biden was not able to make good on that optimistic case. Millions of voters tuned into a matchup between Mr. Biden and Mr. Trump, and the focus ended up on Mr. Biden’s age — and will be focused on that topic for days or weeks ahead — rather than on the issues that could win him the election.

Historically, shifts in the polls after debates can be fleeting. The candidates considered the losers might rebound in the next debate, or manage to turn attention back on their opponent. With many Democrats agonizing over whether to stand by Mr. Biden, it’s hard to see how the race will veer away from questions about the president’s age anytime soon. Worse, Mr. Biden’s performance suggests he might not be able to convince skeptics he’s fit for the job. But should Mr. Biden succeed in satisfying his party’s concerns, Mr. Trump’s low favorable ratings suggest there’s still a path for a closer race.

The Times/Siena data offers less evidence to support another reason polls can shift after a debate: the tendency for the consensus winner’s supporters to respond to polls in outsize numbers. In contrast with the pre-debate poll, Democrats and Republicans responded to this week’s poll in nearly equal numbers (accounting for race), just as they have in almost every Times/Siena poll in the past year. If our last poll was indeed slightly too favorable toward Mr. Trump, it’s possible he’s gained even more ground than the three-point shift shown here.

There’s no way to be sure whether Mr. Biden’s age is his sole problem, a major problem or just one of many problems. Perhaps the lingering resentment over high prices and the border would still give Mr. Trump a lead against a hypothetical young Mr. Biden. The economy, after all, remains the No. 1 issue for voters in the poll. Or perhaps voters are yearning for changes that they doubt Mr. Biden and the Democrats — who have held the White House for going on 12 of the last 16 years — can provide.

But if Mr. Biden can’t convince voters — or Democrats — that he’s fit for the presidency, the other challenges might not matter.