The scary and entirely imaginary notion that millions of noncitizens will vote in November is the most widespread rumor in our politics. It did not just emerge from the fever swamps of the dark web. Rather, it’s a conspiracy theory being pushed, it’s now clear, by leading political figures for partisan gain.

On Sunday, the New York Times reported that former President Donald Trump and Sen. JD Vance are pushing hard the false claim that millions of noncitizens will vote in this election. “When [Kamala Harris] let in millions of illegal aliens,” Vance told a rally in Michigan, “it made our communities less safe — but it did give the Democrats a lot of voters.”

The story paints a disturbing picture that goes beyond the candidates’ claims. Reporter Jazmine Ulloa interviewed voters who said they believed the rumors. “There has got to be a reason they are letting so many people in,” one told her.

It’s worth saying, once again, that the notion of widespread noncitizen voting is a lie. An urban myth. It’s simply not true. States have a multiplicity of systems in place to prevent it from happening. Noncitizen voting is illegal four times over, and the reality is that it’s incredibly rare. My colleagues at the Brennan Center have compiled these resources on the topic. We’re fighting fear with facts.

Yet the idea persists. Why?

Donald Trump has fanned this flame for years. In 2016 — an election he won — he claimed that he really had won the popular vote when you “subtract” what he said were millions of illegal voters.

This fallacy seems to be explicitly designed to sow doubt about the election and its integrity among a wide swath of the voting public. As I told Congress a few months ago, the Big Lie is being pre-deployed ahead of the 2024 election. Donald Trump Jr. told Axios in July that Democrats can only win this November by “cheating.” If millions of Americans believe that there was massive fraud, it will be easier to try to get county election boards to refuse to certify results, state legislators to intervene, or partisan judges to act.

The myth of rampant noncitizen voting also aims to propel voter suppression measures. Recently, the House passed a bill that lays the groundwork to ultimately require citizens to produce a passport or a birth certificate to register to vote. Millions of eligible Amercans don’t have ready access to that paperwork. When you have a “cure” like that, you’d better invent the disease.

But there’s something even uglier at work. More than past rumors about voting machines and ballots, this conspiracy theory taps into innate racism and xenophobia. It plays on the idea that white people are threatened by the possibility that nonwhite people will take over the country. It echoes fears of fraud from earlier waves of immigration, in that case by Irish, Italian, and other European immigrants. It exploits a pressing social challenge — the surge of unlawful southern border crossings and the arrival of millions of migrants — which is the product of vast social and economic forces within and outside our country. And, as in populist movements in earlier eras, it links legitimate public concerns to a conspiracy theory: someone powerful must be enacting a sinister plot.

The great historian Richard Hofstadter described the “paranoid style” in American politics in 1964. “I call it the paranoid style simply because no other word adequately evokes the sense of heated exaggeration, suspiciousness, and conspiratorial fantasy that I have in mind.” He was writing as Americans sought to make sense of authoritarian movements abroad, and movements at home such as McCarthyism and the John Birch Society.

The paranoid style has reemerged. Like many Jewish people, I was a bit baffled when the white nationalists in Charlottesville marched in 2017 chanting “Jews will not replace us.” What they meant was that Jewish elites — who purportedly controlled the government and media — were importing nonwhite people to replace the long-standing white majority. At times, as on the broadcasts of Tucker Carlson, this imaginary scenario is attributed to specific Jews, such as financier George Soros.

It can be agonizingly difficult to rebut a rumor. As Mark Twain reputedly said, “A lie gets halfway around the world before the truth has time to put on its boots.” When fearful people, preyed upon by politicians, hold fast to a misguided idea, it usually doesn’t help to tell them that they’ve been duped.

For now, the most important thing we can all do is bolster the strength and credibility of our election system. Public servants who run elections are still the most trusted voices to explain that elections are fair, free, and accurate. We should all back them up as they come under withering assault, facing abuse and threats of violence.

And we should never tire of pointing out that cynical and aggressive political operatives are stirring these rumors for their own gain.