PHILADELPHIA - Just before midnight Sept 10, Vice President Kamala Harris was about to greet supporters at a post-debate party in Philadelphia when aides pulled her aside with some news she had not been ready for: Taylor Swift had just endorsed her.

For a vice president already riding high from her performance against former President Donald Trump, the blessing of Swift, the 34-year-old megastar – and the most famous childless cat lady in the world – came as a pleasant surprise.

“Hard work is good work, and we will win,” Ms Harris said in brief remarks, leaving Swift’s endorsement to speak for itself. But when the vice president left the stage at the party, a song by the pop star called “The Man” pumped through the speakers: “I’d be a fearless leader / I’d be an alpha type.”

The night was further proof that the Democratic Party’s cruel summer had coasted into a more hopeful election season. In the weeks since President Joe Biden turned his campaign over to Ms Harris, she has used several high-stakes moments to build out a case against Trump.

But the race remains uncomfortably close, with voters still signaling that they want to know more about Ms Harris. Even after a debate widely seen as a success for her, several of the vice president’s advisers said Sept 11 that they believed the contest would come down to disengaged Americans who might not know which way they will vote, or if they will vote at all.

That is precisely where someone like Swift could make a difference.

In a political landscape with countless celebrity endorsements that do little to prompt would-be voters into action, Swift’s support stands out as among the most meaningful: Last year, her post encouraging Americans to vote racked up 35,000 new registrations on Vote.gov. This time, Swift made her endorsement six days before National Voter Registration Day on Sept 17, and included a link to Vote.gov to nudge her supporters to register. The US Election Assistance Commission did not have new figures immediately available Sept 11.

“It’s not just any celebrity,” said Mr Joel Penney, a professor at Montclair State University who studies how pop culture influences American politics. “The fact that these fans so closely identify with stars, there are few examples we can find in pop culture right now with that kind of strong relationship.”

The endorsement of Ms Harris and her running mate, Governor Tim Walz of Minnesota, was not simply a saccharine gesture of support. (Swift baked cookies decorated with the Biden-Harris campaign logo before the 2020 election.) Instead, the singer tied her decision to speak now to a raft of AI-generated messages that falsely appeared to show her supporting Trump.

Swift, a cultural force who knows all too well what it is like to have men try to claim what is hers, snatched back control as she spoke directly to her 283-million-strong Instagram following.

“It brought me to the conclusion that I need to be very transparent about my actual plans for this election as a voter,” Swift wrote in her caption. “The simplest way to combat misinformation is with the truth.”

She also took a swipe at Senator JD Vance of Ohio, Trump’s running mate, who has said that “childless cat ladies” like Ms Harris had no “direct stake” in the country’s future. Swift posted a photo of herself holding her cat, Benjamin Button, and signed the message “Taylor Swift, Childless Cat Lady.”

Mr Walz, another high-profile cat lover, said in a post-debate appearance on MSNBC that he was “grateful” for Swift’s support. (The Walz family adopted Honey, a rescue cat, last December. Though shy, she sometimes lounges side by side with the family dog, Scout, or lies on top of the newspaper when Mr Walz is trying to read it. Honey has her own feelings about life in the spotlight.)

Trump, for his part, has praised Swift as “beautiful” but “liberal” and has noted that, as president, he signed into law a bill that changed how musicians receive song royalties, which he claimed financially benefited artists like Swift. In February, he suggested that it would be “disloyal” for her to vote for Mr Biden. On Sept 11, he warned of the consequences of her endorsement of Ms Harris.

“She seems to always endorse a Democrat,” Trump said Sept 11 morning on Fox News. “And she’ll probably pay a price for it in the marketplace.” A representative for Swift did not respond to questions about the endorsement Sept 11.

For more than a year, campaign staff members in Wilmington, Delaware, who ran Mr Biden’s bid and then Ms Harris’, viewed the Pennsylvania-born pop star as an object of distant fascination. They never successfully made contact, but that did not stop the yearning.

The endorsement was a surprise to the vice-president, her advisers and officials who manage celebrity relationships outside the campaign, according to an official who was not authorised to speak about the plans. But within 20 minutes of the endorsement post, the Harris campaign was nodding to Swift’s fans by selling “Harris-Walz friendship bracelets” on its website for US$20 (S$26) – a campaign aide came up with the idea and officials drew up plans within minutes. By midday Sept 11, the bracelets were sold out.

On Sept 11 afternoon, the Harris team sent out a fundraising appeal asking would-be donors to “join Taylor Swift in supporting” the campaign by sending US$25.

Surrogates for the Harris campaign were elated to hear the news, including Governor Josh Shapiro of Pennsylvania.

“Her speaking out is a big darn deal,” he said. “Wyomissing’s own, Berks County’s own, Pennsylvania’s own Taylor Swift – that’s a huge endorsement.”

Swift has dipped her toe into high-profile races before. But it was only a handful of years ago that she and her team deliberated at length over whether she should involve herself at all.

In the 2020 Netflix documentary “Miss Americana,” Swift and her team argue about whether it is wise for her to endorse a Democrat, Mr Phil Bredesen, over a Republican, Ms Marsha Blackburn, in Tennessee’s Senate race during the 2018 midterms.

“Why would you?” Swift’s father, Scott, asked her. “I mean, does Bob Hope do it? Did Bing Crosby do it?”

Swift held firm. Though she did not say which presidential candidate she voted for in 2016 – a decision she says in the documentary that she regretted – she went on to endorse Mr Bredesen, who later lost the race.

“It really is a big deal to me,” she told her father, her voice cracking.

“It put a spring in my step, I’ll tell you that,” Mr Bredesen said in an interview Sept 11, though it did not ultimately sway the race in his favour. He had not solicited an endorsement from Swift, whom he had first met when she was an “up-and-coming young music star.”

She also endorsed Representative Jim Cooper of Tennessee in his 2018 race for reelection.

Ms Lisa Quigley, who served as Cooper’s chief of staff at the time, said Swift had given their team no advance notice before her post Oct 7, 2018, outlining her concerns with Blackburn – and confirming her intent to vote for both Democratic candidates in Nashville.

“I immediately called Cooper, and I said, ‘Taylor Swift just endorsed you and Phil,’ and he said, ‘Oh, that’s nice’,” Ms Quigley recalled. “Then he called me back about 10 minutes later: ‘My daughter tells me this is a big, big deal and I should be much more appreciative, so for the record, I’m very appreciative.’” NYTIMES