Soon after Kamala Harris and Donald Trump left the Philadelphia stage following the United States presidential debate, musician Taylor Swift threw her support behind Harris.

Swift posted a picture of herself and her pet cat on Tuesday night with a lengthy caption explaining why she will be voting for Democrat Harris and her running mate, Tim Walz.

The endorsement came after months of fevered speculation over whether and when Swift, arguably the biggest name in the world of music, would publicly pick a candidate in the US election.

But could Swift’s support really make a difference and bring more votes to Harris? Here’s more about the role of celebrity endorsements in US elections.

A Swift endorsement

In the caption of her Instagram post on Tuesday, Swift began by saying she watched the debate, urging her 284 million followers to do their research on the key issues and candidates before the November 5 election. “As a voter, I make sure to watch and read everything I can about their proposed policies,” she wrote.

She then expressed fears around the misuse of artificial intelligence to spread misinformation. In August, Trump, on his online platform Truth Social, posted AI-generated images of Swift and her fans appearing to endorse Trump. Some of these AI deep fakes showed her fans wearing T-shirts with the text “Swifties for Trump”.

These images caused Swift to conclude she needed to “be very transparent about my actual plans for this election as a voter”, she continued in her caption before declaring that she would be voting for Harris and Walz. She added that she was heartened by Harris’s choice of Walz as her vice presidential candidate because of his long advocacy for “IVF and a woman’s right to her own body”.

She signed off as “Childless Cat Lady”, a wry nod to Trump’s running mate, JD Vance, who had previously used the phrase to describe emerging leaders within the Democratic Party, including Harris.

Do celebrity endorsements make a difference?

While some polls show that people say they are not influenced by celebrity endorsements, nonprofits and other organisations have reported increased voter participation after celebrities weigh in on a political race, according to a study by Harvard University’s John F Kennedy School of Government that was published in August.

An example of this is Swift herself. In September 2023, she sent out a post urging her followers to register themselves as voters on Vote.org. After this, the nonpartisan, nonprofit organisation recorded more than 35,000 voter registrations. While it was unclear how many of these registrations came from Swift fans, Vote.org reported a 1,226 percent increase in participation in the hour after Swift’s post.

According to the Harvard study, directing fans to register as voters is a common call to action among celebrities. In 2020, YouTube vlogger David Dobrik and, in 2022, model and socialite Hailey Bieber ran online campaigns urging their followers to verify their voter registration status. Both campaigns were successful.

A celebrity endorsement “won’t impact voters who already have strong partisan allegiances, and most voters are in this category”, Richard T Longoria, an associate professor of US government and politics at the University of Texas Rio Grande Valley, said.

Longoria, who specialises in celebrity politics and public opinion, added that a small segment of voters can be influenced by such endorsements. “People that are disengaged from the political process or are discovering political issues for the first time can be influenced,” he said.

“In a close election, that could mean the difference between winning and losing,” Longoria said.

But in terms of celebrity endorsements impacting voter turnout for specific candidates, no modern example comes close to the advantage Barack Obama gleaned from the support he won from the queen of talk shows: Oprah Winfrey.

Oprah and the 2008 Obama campaign

In 2007, Democrat Barack Obama announced his presidential bid for the 2008 election and was backed by Oprah, one of the most influential television hosts and producers in history.

This was when Obama was still competing against fellow Senator Hillary Rodham Clinton to be the party’s presidential nominee.

A poll by the Pew Research Center published in September 2007 showed 69 percent of respondents said Oprah’s endorsement would likely have no impact on their vote. However, 23 percent of Democrats said they were more likely to vote for the candidate of Oprah’s choice.

A study by economists Craig Garthwaite of Northwestern University and Timothy J Moore from the University of Maryland found that Oprah’s endorsement resulted in about one million additional votes for Obama.

In addition to higher voter turnout, her support also helped Obama secure more funds for his campaign, according to the 2013 study. Obama won the 2008 election with nearly 53 percent of the popular vote.

Other celebrity endorsements in US elections – a brief history

For decades, celebrities in the US have been vocal about their support for politicians, adding stardust to campaigns.

While data on the impact of this support are limited, some pop culture icons have done more than lend their names.

Frank Sinatra didn’t just endorse Democrat John F Kennedy’s 1960 campaign, he also raised funds and worked the phones, using his inimitable baritone to woo voters in support of his candidate. By the 1970s, though, the Fly Me to the Moon singer had flipped to the other side, supporting Republican Ronald Reagan, a fellow Hollywood star.

In the 1960 election, Judy Garland, the singer and star of The Wizard of Oz, also supported Kennedy and was seen next to him at the Democratic National Convention that year. In 2008, singer Barbra Streisand supported Hillary Clinton’s campaign. She had also supported Bill Clinton’s 1996 bid.

What’s Swift’s track record with endorsements?

It’s mixed: If the past is any guide, her support is no guarantor of success.

In 2018, she endorsed Democrat Phil Bredesen in his Tennessee Senate race against Republican Marsha Blackburn by posting an Instagram story to her then-112 million followers.

Swift has lived in Nashville, the capital of the heavily Republican state, since she was 14.

Vote.org reported that within 24 hours after she posted her story, the group saw 65,000 new voter registrations. Within three days, the number of registrations rose by an additional 250,000. Again, while it was unclear how many of these registrations came from Swift fans, this was record engagement for Vote.org.

Her 2020 documentary, Miss Americana, features a clip of her tearfully explaining to her parents why she wanted to publicly endorse Bredesen. This video was taken before she went ahead with posting the Instagram story.

“I need to be on the right side of history,” Swift said, adding, “It really is a big deal to me.” She explained that this was because Blackburn “votes against fair pay for women, votes against the reauthorisation of the Violence Against Women Act, which is just protecting us from domestic abuse and stalking”.

Bredesen lost to Blackburn, who won 54.7 percent of the vote.

However, she endorsed Biden in October 2020, and he won the 2020 election with 51.3 percent of the popular vote.

Key celebrity endorsements so far in this election

Here is a look at some of the celebrities endorsing either Trump or Harris in this presidential campaign.

Celebrities endorsing Trump:

• Jason Aldean, a country singer from Georgia, has had a close relationship with Trump recently. He accompanied the presidential candidate at the Republican National Convention in July, Rolling Stone magazine reported, calling the singer Trump’s “golfing buddy”.
• Hip-hop performer, producer and fashion designer Ye, formerly known as Kanye West, has supported Trump since 2016, and the two seem to have maintained a close relationship. Ye endorsed Trump in February, according to a paparazzi video. It was reported that his relationship with the Republican was fractured in 2022 when Ye announced his own presidential bid, but based on the video, relations between the two seem to be back on track.
• Azealia Banks, 33, a rapper originally from Harlem in New York City, has endorsed Trump in interviews with local media. She was also spotted at a Trump election rally in Doral, Florida, in July.
• Miami rapper Gazzy Garcia, known as Lil Pump, routinely posts in support of Trump on his X platform. In September, the Gucci Gang singer, 24, acknowledged this by posting: “I endorse [Trump] multiple times a day I’m all MAGA,” referring to Trump’s slogan, “make America great again”. In January, US media reported that the rapper posted a picture of what seemed to be his leg with Trump’s mugshot tattooed on it.
• Country singer Billy Ray Cyrus performed at the funeral for Corey Comperatore, who was shot during the assassination attempt on Trump at a Pennsylvania campaign rally in July. American music magazine Billboard reported that Cyrus supports the Republican candidate.

Celebrities endorsing Harris:

• Actor and filmmaker George Clooney endorsed Harris in July. Clooney also thanked Biden for deciding not to seek re-election.
• Halloween and Freaky Friday actress Jamie Lee Curtis posted an endorsement of Harris in an Instagram post in July.
• The Office actress and director Mindy Kaling has shown staunch support for Harris and was also present at the Democratic National Convention. “Both of our mothers were immigrants from India who came to America and committed their lives to serving others,” she said at the convention.
• Zoolander actor Ben Stiller, alongside other comedians, joined the virtual “Comics for Harris” rally in August.
• In July, British singer Charli XCX posted “kamala IS brat” on X after releasing her album Brat, sending shockwaves through the internet and shaping a rebrand for the online Harris campaign. Within a day of the rebrand, the followers on the campaign’s X account grew by more than 500,000.