In the hours following Kamala Harris and Donald Trump’s first, and possibly last, in-person face-off, political commentators and unofficial polls seemed to largely crown her the winner of the night.

A CNN poll revealed that debate watchers declared Harris a winner by a comfortable 63-37 margin. A YouGov poll had Harris winning by 43-28 among registered voters. Even pundits at Fox News, the conservative TV network, agreed she bested Trump.

Harris rattled Trump, baited him on the size of his rallies, and both she and the moderators pushed back and instantly fact-checked some of his most extravagant claims. While she did not offer much substance on some of the issues most pressing to voters — like immigration — she exuded a level of confidence critics previously said she lacked and left the debate stage beaming as her opponent stewed.

Then, to top the evening off, Taylor Swift endorsed her.

It may all matter little. Official post-debate polls of undecided voters have not been released yet and will take several days, but it is not clear whether either candidate’s performance will change many minds.

But did Harris actually win, or did Trump just unravel, making her the winner?

Al Jazeera checked in with half a dozen experts on debating, political speech, psychology and communications. Some said she successfully tapped into his weaknesses, while others noted that her strategy aimed at unsettling him, but came at the cost of failing to tell voters more about her own policies. Others questioned the value of political debates at all, decrying a spectacle of little substance and utility to undecided voters.

People watch the presidential debate between Republican presidential nominee former President Donald Trump and Democratic presidential nominee Vice President Kamala Harris, Tuesday, September 10, 2024, at the Gipsy Las Vegas in Las Vegas [John Locher/AP Photo]

She knew what buttons to push

“She won the debate and not just by default,” Tomeka M Robinson, a professor of rhetoric and public advocacy at Hofstra University, told Al Jazeera.

Still, Robinson added, Trump did himself no favours by failing to stick to the issues.

“Trump needed to talk about his policy ideas more rather than relying on leaning into the same dangerous rhetoric about immigrants and reproductive justice,” she said. “He was correct in pushing VP Harris on the issue about the tariffs and that President Biden did not discontinue these. If he would have stuck to his success in certain policy decisions, the debate could have gone differently.”

Tammy R Vigil, a media professor at Boston University focused on political communication also stressed that while Harris exploited Trump’s weaknesses to her advantage, she failed to offer specifics about her policy plans.

“Harris won the debate because she knew exactly what buttons to push to help Trump express himself in the manner that is most revealing of his character,” Vigil told Al Jazeera. “His content is very rarely fact-based and often relies heavily on urging emotional rather than rational responses from viewers. He did the same last night.”

Giving explicit answers about her policies did not appear to be Harris’s priority.

“Harris has adopted the persona of the prosecutor during this campaign,” David A Frank, a rhetoric professor at the University of Oregon told Al Jazeera. “Her strategy in the debate was to put Trump on trial,” he added.

Increasingly angry and incoherent

Some experts contrasted Trump’s demeanour on Tuesday night to his previous presidential debate this year — which eventually led to President Biden’s withdrawal from the race after a disastrous performance.

“In the first debate, while Biden was mainly the agent of his own destruction, Trump did help by sitting back, staying calm, and staying largely on-message,” Nick Beauchamp, a political science professor at Northeastern University whose work includes modelling political debates, told Al Jazeera.

“In the Harris-Trump debate, by contrast, Harris’s constant needling, jibes, and minor insults appear to have played a large role in causing Trump to perform poorly, with increasingly angry and incoherent diatribes,” he added. “So in that sense, Harris did actively cause Trump to lose, though more by actively causing Trump to act badly than by actively presenting herself in the best light.”

Harris, by contrast, did little to define herself and her values clearly, foregoing that opportunity in favour of what appeared to be a deliberate effort to unsettle Trump. “She didn’t do much to define herself or her policies in the positive sense,” said Beauchamp.

Nothing hurts him

While fact-checkers found plenty to fault Trump on, some commentators warned against ruling Harris the winner, noting that the former president has long proven to be resilient to blunders and preposterous claims that would be career-ending for most other political candidates.

Fairly evaluating a debate is not easy when one candidate seems to be immune to all expectations of truth-telling while the other is expected to meet conventional criteria, such as delivering clarity on policy, said Steven Fein, a professor of psychology at Williams College who studies political debates.

Fein pointed to a long list of obvious falsehoods proclaimed by Trump on Tuesday — including about the execution of babies, migrants stealing and eating family pets, and Harris meeting with Vladimir Putin just before the invasion of Ukraine.

“That is not only not disqualifying, but it doesn’t hurt him,” said Fein. “Undecided people say they see no differences between the candidates because Harris didn’t offer specifics about her policies. It is like comparing apples with washing machines, let alone oranges.”

Not a real debate

Had the debate been scored like college competitions are, a judge would have looked at claims made and supported by credible evidence by each participant, James M Farrell, who teaches argumentation and rhetorical theory at the University of New Hampshire, told Al Jazeera.

On Tuesday, Farrell added, there were many dubious claims and little credible evidence, as well as too many “ad hominem attacks, grounding fallacies, non sequiturs, question-begging fallacies, and strawman fallacies on the part of both candidates,” he added. “This made the debate an unpleasant experience for any voter seeking a civil discussion of our nation’s problems and potential policy solutions.”

That may ultimately be the problem with presidential debates that have become entertainment events more than informative sessions intended to guide voters’ decisions.

“These performances aren’t really debates at all,” said Farrell. “As a template of rational and civil exchange of divergent political views, this whole spectacle was miserable.”