Poll: Just 8 per cent said Swift approval would make them more likely to vote for Ms Harris, with 20 per cent saying they’d be less likely

Taylor Swift’s endorsement of Kamala Harris appears to have backfired, according to a poll.

A new poll from YouGov released Saturday found that only 8 per cent of voters said the superstar’s approval would see them “somewhat” or “much more likely” to vote for Ms Harris.

But the same poll, which ran on Sep 11 and 12, found one in five (20 per cent) of those surveyed would be less likely to vote for her after the endorsement.

Immediately after the Trump-Harris TV debate on Tuesday, Swift posted on Instagram: “I’m voting for @kamalaharris because she fights for the rights and causes I believe need a warrior to champion them,” to her 284 million Instagram followers, urging them to register to vote and make their own choice.

Her post drew 10.4 million likes and the vote.gov website received 405,999 visitors in the 24 hours after Swift shared a custom URL with followers.

Ms Harris aides say they would love for Swift to actively campaign, such as by appearing at a rally in her native Pennsylvania, a battleground state that could well decide the election.

But the polling might suggest this wouldn’t be in her best interests.

The Harris campaign itself was not involved in Swift’s decision to back Harris.

The vice president’s aides said they learned of Swift’s support only when the entertainer, 34, posted minutes after the vice president stepped off the debate stage in Philadelphia on Tuesday night.

What difference does a celebrity endorsement make?Celebrity endorsements have shaped recent elections.

A 2008 Northwestern University report found Oprah Winfrey’s endorsement added a million votes to Barack Obama’s tally.

But a 2010 North Carolina State University report found celebrity endorsements by George Clooney and Angelina Jolie did little to move the political needle.

Margaretha Bentley, a professor at Arizona State University whose class studies Swift’s social importance, is unsure whether the pop singer will have an impact. She asked her students earlier this year whether a Swift endorsement would matter. Some said they would follow Swift’s lead and others said it would prompt them to do more research.

And the poll appears to back Ms Bentley’s view – with 66 per cent saying the celebrity nod of approval would make no difference to how they vote on Nov 5.

Almost half, 40 per cent, of respondents said they watched every minute of the debate and a further 21 per cent said they watched parts of it.

Asked whether the debate itself had caused them to change their vote, 6 per cent said yes, while 76 per cent were sticking to their guns.

Ms Harris won the debate, according to 46 per cent of those surveyed, and 44 per cent thought the debate would increase the chances of her winning the election.

Just 19 per cent thought Donald Trump won the debate.