How to Know Who Won and Who Lost Donald Trump-Kamala Harris in Philadelphia

Everyone who watches Donald Trump and Kamala Harris debate on Tuesday night will want to know the answer to a very simple question: Who won?

And while everyone might think they know themselves, in a sea of spin, soundbites, and political posturing there are ways to know who really won. Here’s the Daily Beast’s guide to six key indicators—grounded in history, data, and political performance—which will provide a clearer guide.

Who Dominates the Narrative?

The most obvious way to determine a winner is to see who controlled the narrative (and perhaps talked the most in terms of minutes). Debates are not just about what the candidates say on stage but how their points resonate with the public afterward.

Did one candidate introduce a memorable zinger or a policy proposal that set the tone for post-debate coverage? One of the most famous examples of narrative control was Ronald Reagan’s 1980 debate with Jimmy Carter, when Reagan’s simple question to voters—“Are you better off than you were four years ago?”—became the defining takeaway. It encapsulated voter frustration with Carter’s presidency and was followed by Reagan’s landslide victory.

In the case of Trump and Harris, whoever manages to turn the conversation their way—whether it’s through a punchy one-liner or a clear vision for the future—will likely claim the debate crown.

If Trump, known for his inflammatory rhetoric, successfully redirects attention away from his felony conviction and legal battles and toward economic or cultural issues that play well with his base, he could steer the post-debate narrative.

Harris, on the other hand, would need to harness her skills as a prosecutor to trap Trump in contradictions or force him into unflattering positions on key issues, particularly abortion. to take control of the narrative.

Polling and Data

Historically, snap polls taken after debates have offered immediate data points to assess public reaction. These polls may not tell the whole story but provide a snapshot of who performed better in the eyes of undecided or independent voters. The first time snap polls became crucial was after the first Kennedy-Nixon debate in 1960, radio listeners thought Nixon won, but TV viewers overwhelmingly felt Kennedy’s calm, confident demeanor made him the victor. The lesson? Perception matters, and polling reflects that perception.

John F. Kennedy Library Foundation/U.S. National Archives/Reuters

In 2020, after the first debate between Trump and Joe Biden, CNN’s snap poll found that 60% of viewers thought Biden won the first debate. Both campaigns will be conducting their own snap polls on Tuesday night—not to predict the election outcome, but to work out what undecided voters think.

But snap polls are not the only ballgame: Expect snap polls to be followed by more detailed polling from major outlets like CNN and pollsters like YouGov to provide a first indication of who emerged stronger. Harris and Trump go into the debate neck and neck in the polls nationally and with some suggestions that she is slightly ahead in the swing states, but with Democratic nerves rattled by a Siena College/New York Times poll putting her behind by one point.

Post-Debate Fundraising and Media Coverage

Winning a debate isn’t just about the immediate reactions—it’s about the long game. In modern campaigns, fundraising spikes after debates can signal a strong performance. For example, after her breakout moment in the first 2019 Democratic debate, Harris herself raised $2 million in just 24 hours, The New York Times reported, largely thanks to her sharp exchange with Joe Biden on busing and racial issues. If a candidate sees a dip in donations or struggles to galvanize their base, that can indicate a loss. Harris just reported a massive fundraising edge over Trump so the next set of official fundraising returns will be a clear barometer of success.

Media coverage also plays a critical role. Did mainstream outlets declare a clear winner? Are social media platforms buzzing more about one candidate’s performance? In the 2012 debate between Mitt Romney and President Barack Obama, Romney’s aggressive first-debate performance gave him a significant media boost, even though Obama handily won re-election. Post-debate headlines, social media metrics, and the volume of fact-checks for each candidate can all indicate who captured more attention—and perhaps, more voters.

Body Language and Composure

A candidate’s body language often speaks louder than their words. Nonverbal cues like maintaining eye contact, looking confident, or appearing rattled under pressure can drastically influence how a candidate is perceived. In the infamous 1992 town hall debate, George H.W. Bush’s glance at his watch as a voter asked him a question became a symbol of disengagement and hurt his image. Likewise, Al Gore’s frequent sighs during his debate with George W. Bush in 2000 became a focal point for criticism, overshadowing his policy points.

When assessing the Trump-Harris debate, pay attention to who appeared calm and composed versus agitated or defensive. If Trump, who often relies on aggressive posturing, manages to stay composed while Harris rattles him with sharp critiques, that dynamic could shift perceptions. Conversely, if Harris shows frustration or appears overwhelmed, that might signal a loss of control.

Fact-Checking and Accuracy

In the era of misinformation, post-debate fact-checking has become more important than ever. Candidates frequently make exaggerated or false claims during debates, and these inaccuracies can undermine their performance if exposed. For instance, during the 2016 presidential debates, Trump’s frequent misstatements were fact-checked rigorously, which damaged his credibility with voters and contributed to the view he had lost the debates. Conversely, Hillary Clinton’s focus on policy details and sticking to facts often bolstered her perceived winner status, even if it didn’t lead to an electoral victory.

Rick Wilking/Reuters

In the Trump-Harris debate, both candidates are likely to face intense scrutiny. Fact-checkers from outlets like The Washington Post, FactCheck.org, and PolitiFact will be on standby to verify their claims. The candidate who emerges with fewer fact-checking hits may be perceived as more trustworthy and competent—especially among undecided voters who value honesty and integrity in their leaders.

Blunders and Mistakes

Perhaps the most glaring indicator of a debate winner—or loser—is who shot themselves in the foot.

A high-profile gaffe can overshadow any strong moments a candidate may have had, often sticking in voters’ minds long after the debate ends. In 1976, Gerald Ford made a major blunder when he claimed that “there is no Soviet domination of Eastern Europe,” a statement so factually inaccurate that it became a defining moment of his campaign and eroded his credibility.

Brian Snyder/Reuters

Similarly, Rick Perry’s infamous “Oops” moment during a 2011 GOP primary debate, when he forgot the third government agency he would eliminate, was a fatal error that torpedoed his presidential aspirations. And that’s not to mention Biden’s June performance which cost him his shot at a second term.

If either Trump or Harris makes a significant mistake—whether it’s a glaring factual inaccuracy, an unforced error, or a gaffe that resonates negatively—it could become the defining moment of the night. Trump, known for his off-the-cuff style, runs the risk of delivering a controversial or inflammatory remark that could alienate undecided voters. Harris, while typically more measured, can blunder as a result: an overly scripted phrase could be amplified by Trump’s aggressive tactics.