Hours before President Trump took the stage at the University of Tennessee at Chattanooga on Sunday night, Rihanna’s “Don’t Stop the Music” reverberated through the 11,000-seat McKenzie Arena. “Trump’s rallies are unlike anything else in politics,” The Washington Post’s Philip Rucker wrote on Twitter, where he described the scene: staff members throwing Trump T-shirts into the crowd “like a ball game,” lines stretching out the doors.

“Keep on rockin' to it,” Rihanna’s recorded voice sung out. “Please don’t stop the, please don’t stop the, please don’t stop the music.”

But when the pop star learned that her 2007 hit song had been featured at the rally, her response was unambiguous: She did, in fact, want the music to stop.

“Not for much longer,” she tweeted, in response to Trump using her song. “... me nor my people would ever be at or around one of those tragic rallies.”

The Barbadian singer can’t vote in the United States but has made no secret of her political leanings: She has been a vocal critic of the president. Last year, she called him an “immoral pig” after he signed an executive order banning citizens of seven majority-Muslim countries from entering the United States in January 2017 and criticized his response to Hurricane Maria’s devastation in Puerto Rico.

Weeks before the 2016 election, Rihanna was spotted wearing a T-shirt with a photograph of Hillary Clinton’s face screenprinted on it. After Trump’s inauguration, she showed up at the Women’s March in New York in a pink sweatshirt and matching tutu and dabbed in front of Trump Tower.

But can she actually stop Trump from playing her music?

The answer is complicated. When a politician wants to use a song as background music at a rally, their campaign needs a public performance license from the copyright holder of the musical composition, rather than one from the recording artist, intellectual property lawyer Danwill Schwender explained in a 2017 article in “American Music,” a scholarly journal published by the University of Illinois Press. Radio and TV ads are another story — the owner of the sound recording, typically the artist’s label, will need to license the song to the campaign.

In the United States, the copyrights for most musical compositions are administered by one of two performance rights organizations: The American Society of Composers, Authors and Publishers (ASCAP) or Broadcast Music Inc. (BMI), which represent 23.5 million songs between them. In 2012, BMI created a separate license for political entities, Schwender wrote, which allows musicians to opt out if they don’t want their songs used at rallies. ASCAP has a similar provision in place, according to NPR.

Musicians from Adele to Neil Young have requested that Trump stop playing their songs at his campaign stops, and some have taken advantage of that clause. In October 2015, Aerosmith frontman Steven Tyler demanded that the Trump campaign stop playing “Dream On” at rallies, and BMI pulled public performance rights for the song. (Trump’s Aug. 21 rally in Charleston, W. Va., featured Aerosmith’s “Livin' On the Edge,” prompting another cease-and-desist letter from Tyler.) Similarly, after the Republican National Convention licensed Queen’s “We Are the Champions” in 2016, the band chose to exclude the song from being used for future political events.

As The Post’s Amy B Wang reported last week after Pharrell Williams asked Trump to stop using his 2013 hit “Happy” at political events, the ASCAP warns politicians that even if a campaign has obtained a license to use a song, they should still get the artist’s permission. According to the ASCAP’s guidelines, disgruntled artists could file suit under the Lanham Act, which is intended to prevent the dilution of a brand’s trademark through unauthorized use or under “right of publicity” laws which provides image protection for well-known artists in some states.

But as Forbes’s Melinda Newman wrote, “The problem is that both of these are untested as far as campaign usages since no artist or songwriter seems to have ever taken a case to trial citing a violation by a campaign—or at least as far as we could find. "

Meanwhile, Trump famously likes to end his rallies with the Rolling Stones’ “You Can’t Always Get What You Want,” even though it’s against the band’s wishes. And there’s not much the group can do to stop him, Mick Jagger said in 2016.

“So, the thing is, when you appear in America . . . if you’re in a public place like Madison Square Garden or a theater, you can play any music you want, and you can’t be stopped,” Jagger said in a question-and-answer session on Twitter. “So, if you write a song and someone plays it in a restaurant that you go to, you can’t stop them. They can play what they want.”

Most of the typical venues for campaign events, such as arenas and convention centers, will already have a blanket license from a performance rights organization in place, Schwender wrote. And that’s why “Sweet Child O’ Mine” gets played at Trump rallies despite Guns N’ Roses’ requests to the contrary, Axl Rose said on Sunday.

“Unfortunately the Trump campaign is using loopholes in the various venues’ blanket performance licenses which were not intended for such craven political purposes, without the songwriters’ consent,” he wrote on Twitter.

In his article, Schwender noted that the RNC could theoretically use a convention center’s license to play Queen’s “We Are the Champions” and argue that the venue’s license supersedes the campaign’s license — or lack thereof.

“Although a BMI spokesperson stated that doing so ‘would not be appropriate,’ the use of a song as random backdrop music as opposed to a campaign’s ‘theme music' may alter the analysis,” he wrote. “The courts have not yet tested this argument.”

For musicians, there’s little financial reward in chasing such a lawsuit. And it’s always possible that the campaign might voluntarily choose to stop playing Rihanna’s music after her request, as they did for Young in 2015. But in the meantime, Rihanna’s stance has earned her praise from some Democratic politicians.

“Good for @rihanna,” wrote Rep. Eric Swalwell (Calif.) on Twitter. “@realDonaldTrump also picked the wrong song. Wouldn’t ‘Russian Roulette’ or ‘Rude Boy’ better suit him anyways?”

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