What the polls say ahead of the Harris-Trump presidential debate

The June 27 presidential debate between President Joe Biden and former President Donald Trump was arguably one of the most consequential in modern history, catalyzing Biden's withdrawal from the race on July 21, less than a month later. The contest has completely changed since then, with Vice President Kamala Harris ascending to the top of the ticket and surpassing Trump in the polls, signaling that she may be overcoming some of the deficits that voters saw in Biden's campaign.

Now it's time for another debate.

Harris comes into this debate riding relatively high on climbing approval ratings and a small lead in national polling, as well as a wave of enthusiasm among her base following the Democratic National Convention in late August. Her performance Tuesday night in Philadelphia could either continue the upward trajectory or bring it to a halt, particularly as more undecided voters are likely to tune in than usual.

With that in mind, we dug into the numbers to see what's on voters' minds heading into the first Harris-Trump presidential debate. Recent polling suggests that voters view Harris's campaign fairly favorably so far and think she's favored to win the debate. Meanwhile, Trump still has an edge on some of the most important issues on voters' minds, but he may be vulnerable to the same age-based attacks that his side once lobbed at Biden.

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From the time she became the presumptive Democratic nominee, Harris's favorability has shot up. In 538's latest average, it's about 46 percent, just short of her disapproval rating. That's much better than where she was right before Biden dropped out, when she was underwater by around 15 points:

Harris's favorability surge represents a notable improvement over Biden, who's been mired at around a -15 net favorability rating for most of this year, and it's also notably better than Trump, whose rating has remained mostly flat since the start of 2024. In our most recent average, he remains almost 10 points underwater (53 percent view him unfavorably and 43 percent favorably).

In an ABC News/Ipsos poll taken Aug. 23-27, 56 percent of adults said Harris is doing an excellent or good job on her campaign, compared to 41 percent who said the same of Trump, and 53 percent said she is very or somewhat qualified to serve as president, compared to 47 percent who said so of Trump. And in the all-important horse race, she's currently ahead of Trump in 538's national polling average by about 3 points in head-to-head matchups — though her momentum looks to have stalled or slipped slightly in the last couple of weeks:

We appear to be at the tail end of a honeymoon period for the Harris campaign, and polls suggest that’s because her candidacy energized some of the many voters who were disillusioned and unexcited about the rematch between Trump and Biden. Indeed, in that same ABC News/Ipsos poll, 64 percent of her supporters said they strongly supported her, compared with only 34 percent who said the same of Biden in early July. Forty-five percent in the August poll also said they were very or somewhat satisfied with the choice between Harris and Trump for president, compared to only 28 percent who said the same about Biden and Trump in July.

Voters seem to be bringing some of their good vibes about Harris into their debate expectations too. In the ABC News/Ipsos poll, a plurality of respondents (43 percent) said they expect Harris to win Tuesday's debate, compared to 37 percent who said they expect Trump to win. That's reversed from the last debate, where voters expected Biden to perform poorly (and do worse than Trump) even before the debate. While higher expectations are a good sign for how Harris's campaign has been doing, they likely also mean that she has a higher bar to clear than Trump when it comes to impressing voters and meeting expectations. That’s one reason this week’s debate could be critical in whether Harris’s honeymoon period translates into sustained gains, or fizzles out.

So, what might voters be looking to hear from Harris and Trump in the debate? When it comes to the issues, both candidates will be looking to hold their ground on issues that they have an advantage on, while cutting into their opponents' lead on areas of weakness. Trump in some ways starts off with the high ground on key issues. The ABC News/Ipsos poll showed Trump with an advantage of 8 points over Harris when it comes to whom Americans trust more to handle inflation and the economy. Trump also had a 9-point advantage on the issue of immigration at the U.S.-Mexico border, and a 7-point advantage on handling the war between Israel and Hamas.

Harris has an even larger advantage over Trump on her strongest issues in this poll: 16 points on abortion and race relations, and 10 points on health care. But other recent polling has shown that voters rank those issues as less important in determining their vote than the economy and immigration. (Health care and abortion ranked just after those two issues on a similar list, while race relations was among the least important to voters.) We'll expect both candidates to talk up signature issues like abortion (for Harris) and immigration (for Trump), but we'll also be looking out for how Harris tries to shift the narrative on the economy and immigration — and how well Trump stays on topic to bolster his advantage on those issues.

Of course, debates are often as much about style as substance: Voters will be keeping a close eye on how the two candidates act on stage, or who seems more "presidential." And when it comes to personal attributes, Harris generally outperformed Trump. Respondents in the ABC News/Ipsos poll were particularly likely to view her as more honest and trustworthy than Trump, 43 percent to 25 percent, and she came out ahead when respondents were asked which candidate represents their personal values and understands the problems of people like them.

Notably, Harris also beat out Trump by a large margin when it came to who Americans think has the better "physical health" and "mental sharpness" to serve effectively as president, with more than twice as many saying Harris was in better physical health (57 percent to 25 percent). That difference underscores one of the most obvious ways Harris's candidacy changed the dynamic of this race — she's around 20 years younger than both Biden and Trump — and raises the question of whether Trump will face some of the same age-based concerns that drove Biden out of the race.

Little about this presidential contest has been traditional, and after a first presidential debate blew open the presidential race in June, this debate is expected to attract more eyes than usual. In an unusually abbreviated race between Harris and Trump, the candidates have had a short amount of time to make their cases to voters, and this week's debate will be one of the most high-profile, and-high stakes, opportunities to do so. The country will be watching to see if Harris meets high expectations, and how Trump responds in their first head-to-head matchup.