Halfway through their encounter Tuesday night in Philadelphia, Trump assailed Harris over US border policy and claimed that migrants in the Ohio city of Springfield were “eating the pets of the people that live there.” ABC News moderator David Muir interjected quickly to clarify that the network had contacted the city’s manager, who said that there were no credible reports of pets being harmed by immigrants.

Trump’s assertion echoed apocryphal stories circulating worldwide on X and other social media sites that Haitian migrants in Springfield were behind a wave of local crime and to blame for the disappearances of cats and dogs. Supporters of the former president — including X owner Elon Musk, who has nearly 200 million followers on the platform — promoted and reposted the claims in the days before the debate.

The episode highlighted the risk for political candidates, including Trump and his right-leaning allies, of embracing conspiracy theories that don’t survive the light of day off social media. It quickly turned into a focus of derision toward Trump and a symbol of everything that had gone wrong for the former president during his debate with Harris. By Wednesday morning he was signaling that there might not be a rematch.

Trump has been trying to emphasize immigration in his campaign against Harris and pivoted to it often during the debate, but repeating the falsehood about the Haitian immigrants in Ohio won’t help the former president, said Alex Conant, a Republican strategist and veteran of Marco Rubio’s 2016 presidential campaign.

“At best, it’s a distraction,” Conant said. “At worst, it reminds people of the all the craziness that comes with Trump.”

The situation in Springfield had been “largely ignored by the liberal mainstream media until now,” said Trump campaign spokeswoman Karoline Leavitt. “President Trump will continue giving a voice to Americans who are expressing their concerns about the influx of illegals and rising migrant crime in their communities.” 

Prominent personalities often seize on trending narratives to find an audience or appeal to their existing followers, according to experts who study disinformation. The ultimate goal often is to amplify their rhetoric, rather than promote talking points based on truth, they said.

“Often times we will see influencers capitalize on conspiracy theories and falsehoods to manipulate or influence public discourse or opinion, even when they don’t believe them because the narratives themselves are preposterous,” said Lisa Kaplan, founder and chief executive officer of Alethea, an anti-misinformation firm. “This is typically done for political, personal, or financial gain — and to generate more engagement online.”

Trump’s comments did appeal to the audience he intended: fans on X, who responded by generating memes using artificial intelligence, which depicted cats, dogs and geese pleading with voters to save them by choosing Trump. Some of those same concepts were used to mock Trump for believing something so extreme.

The conversation is part of a trend on the network, fueled by its owner, Musk, to embrace anti-immigrant sentiment. Musk, who backs Trump for president, previously came under fire for supporting false content that led to violence against migrants in the UK.

“The campaign apparently hopes that spreading claims like these, regardless of accuracy, will foment public hostility toward migrants,” said Jared Holt, senior research analyst at the Institute for Strategic Dialogue. “Hate against migrants and minorities has produced a bloody trail of tragedies in the United States, and leaders who encourage those hostilities create risks for the people they target.”

Since Musk purchased Twitter for $44 billion in late 2022 and remade it into X, he has pushed an anything-goes approach to content on the platform, including by sharply reducing the staff moderating content and by embracing conspiracies himself.

Rumors about Haitian migrants in Springfield were also amplified on X by Trump’s running mate, Ohio Senator JD Vance, in posts on Monday and Tuesday ahead of the debate that logged millions of views. 

About 15,000 Haitians have come to Springfield legally in the past several years under temporary protected status as they flee poverty and violence in their home country. Their arrival has overwhelmed the health-care system and public services in the city of 58,000, Ohio Governor Mike DeWine said on Tuesday. 

DeWine called on the federal government to do more to support communities affected by such surges but cautioned against blaming the Haitian immigrants. 

“Haitians who are here are hard-working people,” DeWine said during a news conference in Columbus before the debate. “They came to Springfield, Ohio, for work, and many, many, many of them are working and filling positions in Springfield.”

(Updates with Trump campaign comment in seventh paragraph)