What impact will Taylor Swift really have on the US election?

Part of the appeal of a celebrity endorsement – and the political content generated by their fandoms – is that unlike paid-for adverts, this kind of user-generated content feels genuine.

A study from Harvard Kennedy School that looked at the impact of celebrities when it comes to voter registration found their “authenticity” can be key when motivating people to go out and vote.

Its author, Ashley Spillane, told the BBC celebrities are among the “most well-positioned members of society” when it comes to dealing with causes of voter apathy, such as “lack of information, lack of trust and lack of motivation”.

“People know them from places outside of politics, which makes their involvement feel deeper and less self-interested,” she said. Within 24 hours of Swift’s Harris endorsement on Instagram, nearly 340,000 people had visited vote.gov, a registration website, using a custom link she created.

While Harris has enjoyed endorsements from Swift, Beyonce and some other big-name celebrities, Trump is not without his fans either. Endorsements from Kid Rock, Elon Musk, John Voight and YouTubers the Nelk Boys may help him reach young men in the same way that Swift’s endorsement has boosted Harris’s profile with young women. Trump’s own committed supporters online also operate a bit like a fandom.

Endorsements can backfire, however, polls show. A Quinnipiac University poll from late September found that Swift’s endorsement of Harris made 9% of respondents “more enthusiastic” about her candidacy, while it made 13% “less enthusiastic”. It also looked at how Musk’s endorsement affected respondents’ views of Trump – 13% felt more enthusiastic, while 21% felt less. Ultimately, we won’t know exactly what impact celebrities – and their fandoms – will have on this election until after November.

In what looks to be a very closely fought election, it’s these groups of online supporters who could motivate voters to head to the polls – especially in swing states where the winner may be decided by just thousands of votes.

Ms Kim, the co-founder of Swifties for Kamala, told me the group is targeting people in swing states especially.

Peggy Rowe is in Arizona, one of the most closely watched states in the election. She told me it was Harris’s support for abortion rights that strengthened her to support for the vice-president.

“I’m very passionate about reproductive rights and social media has further confirmed my opinions,” she said.

While they’re employing all the traditional political campaign methods, Swifties for Kamala has put a fan-specific twist on their efforts. Whenever they’re at events, they give out friendship bracelets featuring political slogans like “in my voting era”. It’s a nod to Swift’s Eras tour, where fans have been trading Swift-themed friendship bracelets as a sign of being a true fan.

Ms Kim said they’d begun face-to-face campaigning a few weeks ago, and have been calling and texting followers directly. They aim to have 22 million direct voter contacts in total by Election Day.

The Swifties for Kamala group has raised over $200,000 (£153,000) for Harris’s campaign, as of the middle of October, she estimated.