When former President Donald Trump told millions of Americans during Tuesday's presidential debate that "our elections are bad, and a lot of these illegal immigrants coming in, they're trying to get them to vote," he was not just repeating a baseless claim intended to undermine the results of the upcoming 2024 election.

He was also echoing the latest iteration of a once-fringe racist conspiracy theory that has now become mainstream in the Republican Party. The conspiracy — known as the "great replacement" — claims there is a plan to bring nonwhite immigrants into the United States and other Western countries to replace white voters to achieve a political agenda.

Throughout this presidential campaign season, Trump and his allies have repeatedly claimed that Democrats allowed migrants to enter the country so they would vote in the 2024 election — despite the fact that no evidence has surfaced of a mass scheme to register undocumented immigrants. Noncitizen voting in federal elections is illegal and rare, and there are checks in place to deter and prevent it. (A small number of localities permit noncitizens to vote in municipal elections for positions such as school board member using separate ballots from those used for state and national elections. The number of noncitizens who ultimately cast ballots is very small.)

"They can't even speak English. They don't even know what country they're in, practically. And these people are trying to get them to vote, and that's why they're allowing them into our country," Trump said during Tuesday's debate.

Social media influencers and groups allied with Trump have sought to keep the issue alive, frequently hyping thinly sourced stories that claim noncitizens are being encouraged to vote but that have turned up no concrete evidence.

NPR has reported that replacement theory has penetrated a much more mainstream portion of American society in recent years. A 2022 poll, conducted by the Associated Press-NORC Center for Public Affairs Research, found that 1 in 3 American adults now believes in a version of it.

Rhetoric with a history of inspiring violence

Cynthia Miller-Idriss, a professor at American University and the founding director of the Polarization and Extremism Research and Innovation Lab (PERIL), said the baseless narrative has become so commonplace in the Republican Party's political rhetoric that she barely registered Trump's invocation of it during the debate.

"Not only did it not shock me — I didn't even hear it," she said.

Miller-Idriss said that replacement theory fits into an array of fears that GOP elected officials and right-wing media outlets like Fox News have stoked around the theme that political elites, a shadowy cabal of power brokers or even undocumented immigrants are trying to rob Americans of something they hold dear.

"Whether it's your Second Amendment rights or your white-majority country or … your votes are being stolen. ... Now your pets are being stolen and then eaten," she said. "I mean, it's so absurd to hear it go to the pets, but it's the same thing. There's always something that's being taken away from you and unfairly given to someone else. That narrative is incredibly powerful."

But Miller-Idriss warns that using replacement conspiracy to motivate people to vote against Democrats is also dangerous. Not only will it prime Trump's base to doubt the results of the election, should he lose, but it is also a narrative that has driven deadly far-right attacks around the world.

"It really mobilizes a fringe to violence," Miller-Idriss said. "We've seen that in Christchurch, we saw it in Oslo, with terrorist attacks in El Paso, in Pittsburgh, in Buffalo. In lots of places, we've seen that exact conspiracy theory mobilized violence."

Two days after the debate, an emailed bomb threat shut down City Hall and multiple municipal facilities in Springfield, Ohio. Springfield was the center of the unfounded claim that Trump amplified during the debate, falsely asserting that Haitian immigrants were eating residents' pets. The bomb threat suggests that untruths about migration may feed threats of violence for some time.

"That's what I'm most worried about," said Heidi Beirich, co-founder of the Global Project Against Hate and Extremism, which tracks domestic and transnational far-right movements.

Beirich said that the normalization of replacement theory may not only feed further domestic attacks but also contribute to an increase in everyday hate crimes against anyone perceived as nonwhite. She noted that hate crimes in the U.S. have already been rising over several years.

"This is going to make the problem worse for anybody who appears to be an immigrant," she said. "Anybody a white supremacist thinks shouldn't be here is a possible target. And that's really scary."

Consequences for democracy

As politicians have echoed replacement theory rhetoric this campaign season and heightened fears around noncitizens voting, officials have taken actions that have consequences for voters.

Eligible voters, especially naturalized citizens but also voters born in the U.S., have been erroneously entangled in efforts by state election officials to flag possible noncitizens on voter rolls in recent months.

After a Fox Business host spread a baseless rumor about undocumented immigrants registering to vote in Texas last month, the state's Republican attorney general launched a criminal probe into voter registration groups — which local advocacy groups say has a chilling effect on lawful efforts to promote voting.

Such efforts could increase "the threat of violence and sense of fear at polling places — and are thinly disguised attempts to intimidate voters of color and naturalized citizens," wrote attorneys Anna Dorman and Kenneth Parreno in a recent newsletter for Protect Democracy, a nonprofit that works to counter authoritarianism.

GOP House Speaker Mike Johnson, who has a history of echoing replacement theory language, is championing the SAVE Act, which would require documentary proof of citizenship to register to vote. He is attempting to tie it to a federal funding bill that must pass by the end of the month to avoid a government shutdown.

"Democrats have expressed a desire to turn noncitizens into voters," Johnson said when he introduced the SAVE Act in May. "That's what this open border has been all about."

In New Hampshire, Republican Gov. Chris Sununu signed a law on Thursday requiring evidence of citizenship when registering to vote and photo identification at the ballot box. The law won't take effect until after November's general election.

Democratic opponents of these measures say the current system is already working to deter noncitizens from voting, as evidenced by the very small number of documented cases.

They also say the proposed federal legislation would make it harder for some eligible U.S. citizens to vote, especially voters of color, who are more likely to lack access to a document proving their citizenship, like a birth certificate or passport.

The decision by Republicans to fixate on this bill on the eve of the election — when it is already too late to change protocols for this contest — indicates the goal is to provide "oxygen for lies in the post-election period if Trump loses," said David Becker, the executive director of the Center for Election Innovation and Research.

"You can absolutely bet if Trump loses, he will claim there was widespread noncitizen voting without any evidence whatsoever," Becker said. "And that is going to incite anger and potentially violence."

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