Breaking News: Will Taylor Swift’s Endorsement Actually Affect the Election?…See More

To some Americans, the biggest news to come out of the presidential debate Tuesday night was not Kamala Harris’s well-received performance. It was Taylor Swift’s endorsement of her minutes after the debate ended.

As celebrity endorsements go, there may not be a bigger one. But could it actually influence the race?

There’s no doubt that Ms. Swift has sway with her legions of fans. There were a total of 405,999 visits to Vote.gov through the link on Ms. Swift’s Instagram story in the 24 hours it was live, far more than the site’s daily average of 30,000 in early September, according to a General Services Administration spokesperson.

But that number alone isn’t particularly useful. It doesn’t tell us whether the visitors were new voters, whether those visits translated into actual registrations or what any new voters will do on Nov. 5.

The reality is that it’s impossible to know exactly how much of a difference — if any — Ms. Swift will make. But here are some ways to think about the question, after looking at research and speaking with college-age Swift fans in Pennsylvania after the debate.

What the research says
There are lots of studies on celebrity endorsements, but the evidence that they matter is mixed. And even if they do matter (they are still sought after and welcomed), the actual effects are very hard to measure.

But researchers have tried.

After Oprah Winfrey endorsed Barack Obama in the 2008 Democratic primary, researchers analyzed Oprah Magazine subscription data, book sales and election results to see if Mr. Obama performed better than expected in places where people subscribed to the magazine or where books recommended by Oprah’s Book Club sold particularly well (after controlling for various demographics like race, age, education and more).

They found that he did, and concluded that Ms. Winfrey’s endorsement resulted in an additional one million votes for Mr. Obama in the primary, out of more than 30 million votes cast.

But this example may only take us so far. Researchers at Miami University in Ohio and California State Long Beach found that celebrity endorsements are more likely to matter in primary elections, when voters must choose between two or more relatively similar candidates. In these situations — when voters don’t really have a strong view one way or another — the voice of a trusted celebrity can play an important role.

Young voters are typically much less likely to vote than older voters. In a close election, if Ms. Swift’s endorsement persuaded even a small portion of Democratic-aligned potential voters to register and cast a ballot, it could make a difference.

Then again, if it did, we wouldn’t necessarily know it: If Ms. Harris sees a bump in polling data or voter registrations, it will be hard to tell whether it comes from Ms. Swift’s endorsement, a strong debate performance or something else altogether.

The endorsement may also have other, less visible downstream effects. It may help with fund-raising or lead to more favorable media coverage.

Campaigns need excitement, but it’s not always easy to gauge. If it has felt to you that a lot of this year’s election cycle has risen and fallen on vibes, you’re not alone. On Tuesday night, the Harris/Walz campaign rushed to offer Swift-inspired friendship bracelets on its website. They sold out in less than 24 hours.