The drumbeat by President Donald Trump and his allies about the perceived threats of voting by people who are not U.S. citizens is getting louder as the November election approaches.

He is pushing to have the U.S. Postal Service send mail ballots only to voters verified as U.S. citizens. The Census Bureau promoted a dubious report about thousands of noncitizens voting in 2020, an election that the Republican lost to Democrat Joe Biden. Trump’s Department of Homeland Security is claiming without providing evidence that 250,000 noncitizens might be on the rolls in just four states.

Last week, the Republican candidate for governor in Maine confirmed an audio recording in which he said he plans to ask Trump’s border czar to send U.S. marshals and U.S. Immigration and Customs Enforcement agents to polling places in the state to ensure that only legal voters are casting ballots.

Evidence of noncitizens voting is continuing to “pile up,” White House spokesperson Lauren Bis said when asked about the census report.

In fact, voting by noncitizens is extremely rare and is punishable as a felony that carries the potential for deportation. Even so, opponents say the hyperfocus on the issue by Trump and his allies is setting the stage for legal challenges to outcomes he may not like during the midterms in which control of Congress is on the line.

“Throw out these deceitful, deceptive claims as an excuse for disruptions,” said Alexandra Chandler, director of impact programs, free and fair elections at the nonpartisan Protect Democracy. “You can deny the results later.”

The census report, which the president cited in a Truth Social post, said it found in a “beginning analysis” that 24,000 noncitizens voted illegally in 2020. It cited data from a commercially available voter file, which was checked against federal records.

Experts say the methodology might have created false positives: for example, if a person’s name was linked to the wrong address or someone’s citizenship status had not been updated in a particular database.

Details that typically would be included in such a report about error rates were missing, said Justin Levitt, a Loyola Marymount University law professor. Nevertheless, election experts say it could help generate distrust among certain voters during this year’s general election.

“This is an empty manila folder that the administration will wave around when it says the elections were fraudulent, noncitizens voted,” Levitt said.

Homeland Security Secretary Markwayne Mullin’s July letter to California, Nevada, New Jersey and Pennsylvania, alleging that as many as nearly 250,000 noncitizens were registered in those states, was met with skepticism and requests for more information.

“I have serious doubts about the reliability of your data and accuracy of your claims, since my office has not shared our statewide voter registration list with DHS or any other federal agency or official,” California’s secretary of state, Democrat Shirley Weber, said in response.

In New Jersey, Mullin’s department indicated as many as 35,000 noncitizens were registered. Shortly after the letter, the Democratic-controlled state disclosed that about 6,600 noncitizens were improperly registered through its motor vehicle system in 2023 and 2024.

Democratic Gov. Mikie Sherrill said those people answered “no” when asked whether they were citizens, but were registered anyway. The governor said her administration found that “fewer than 400” of them had voted and that it has begun replacing the vendor involved in the improper registrations.

Pennsylvania’s secretary of the commonwealth, Republican Al Schmidt, said in a letter last week that DHS officials acknowledged during a recent meeting they did not have high confidence that the 14,576 people referenced in the initial letter were in fact noncitizens improperly registered to vote. He said federal officials said they would provide a methodology and that Pennsylvania officials were awaiting that information.

Nevada Secretary of State Francisco Aguilar, a Democrat, said he did not understand the methodology the federal government used.

“All I can say is we have done significant work to make sure our voter rolls are as clean as possible,” he said.

Messages from The Associated Press seeking comment from DHS were not immediately returned.