In President Trump's prime-time address last month declaring U.S. elections vulnerable, his centerpiece claim was that more than 250,000 noncitizens were registered to vote. A day later, the Department of Homeland Security said the striking number covered just four states.

New Jersey Gov. Mikie Sherrill already knew her state had a problem but nothing of that scale. The day before Trump's speech, the Democrat learned from her state attorney general's office that under the previous governor, the state had accidentally put thousands of noncitizens on its voter rolls. Even worse, hundreds of them appeared to have cast ballots. The governor and her advisers quickly realized they needed to acknowledge the errors.

On July 21, Sherrill said 6,600 noncitizens had been added to New Jersey's voter rolls from June 2023 to June 2024, blaming a software glitch at the motor vehicle commission, which automatically registers eligible people to vote . While applying for a driver's license, these people selected "no" when asked if they were U.S. citizens, Sherrill said, but "the system registered them anyway."

The number of those who voted was relatively small -- fewer than 400, according to Sherrill, in a state with about 6.7 million registered voters. But the revelation stoked an already smoldering national debate, initiated by the White House, over the security and integrity of U.S. elections .

Elections are primarily run by states, and the federal government has traditionally helped share intelligence and cybersecurity warnings. Rather than continue this type of partnership, the Trump administration has instead mobilized federal agencies to sue states to try to force them to turn over their complete voter rolls and threatened chief election officials with prosecution if anyone but U.S. citizens are registered to vote on their watch. The administration also ordered the creation of a mass voter verification system that is tied up in court over alleged inaccuracies and privacy concerns.

State leaders know that the administration's spotlight could land on any one of them, bringing accusations that they held an invalid election. Elections officials say they run secure contests and already check voter rolls, in many cases daily, pruning people who have died, moved or aren't eligible to vote. Some say they are now scouring names even more obsessively.

"I feel like I'm in a UFC chokehold," said Francisco Aguilar, the Democratic secretary of state in Nevada, another of the four states alleged by the DHS to have large numbers of noncitizens on its rolls. "Everything we do has to be perfect."

DHS named New Jersey, Nevada, Pennsylvania and California as the states Trump alleged in his address to have a quarter million noncitizens on their voter rolls. The states have responded to DHS, saying the agency has provided no methodology, proof or details they can use to verify its claims. State officials also say that without access to the full voter rolls, DHS can't make any accurate assessment of noncitizen registration.

A DHS official said the federal department looked at publicly available portions of states' rolls and cross-referenced them with known illegal immigrants in its systems. It's not rocket science, the official said.

The unredacted voter rolls typically link voter records to specific identifiers such as Social Security numbers or driver's licenses, which the federal government could use to make more definitive data matches.

Democrats and some Republicans worry that even small errors in voter registrations will be used by Trump to challenge the outcome of contests in the November midterm elections. The Democratic Party is favored to reclaim a majority in the House and, possibly, the Senate.

Trump in his July 16 address said he ordered DHS to notify every state about noncitizens on their voter rolls. "We've put these governors on notice. States must work with us to ensure free, fair, and honest elections," DHS Secretary Markwayne Mullin said in a statement.

The Trump administration has sued New Jersey and 29 other states for access to their unredacted voter rolls. Federal officials say they believe the rolls could contain vast numbers of erroneous registrations. So far, the federal government has lost its lawsuits in at least 20 district courts and a divided panel on the Sixth Circuit Court of Appeals. It has appealed some of those decisions.

The Trump administration also has appealed to the Supreme Court for permission to proceed with an executive order for federal agencies to create lists of people they consider eligible to vote. A dozen Republican-led states filed their own appeal in support of the administration.

A federal judge has ordered the administration to take its mass voter verification system offline , saying "it haphazardly combined and repurposed the private information of millions of Americans, including citizenship data that they knew to be unreliable." Another judge, though, has ordered that four states that want to use it should be able to do so.

"We like to say in our office that we have an all-hazards approach to planning for elections," whether a bomb threat or extreme weather, said Minnesota Secretary of State Steve Simon, a Democrat. "This year, there's a new hazard that we have to plan for, and that is the possibility that our own federal government might in some way, indirectly or directly, interfere."

White House spokeswoman Lauren Bis said, "The entire Trump administration will continue lawfully enacting the agenda President Trump was elected to implement, which includes the safety and security of American elections."

Motor voters

People applying for driver's licenses or state identification cards who are eligible to vote are automatically registered in about half the states in the U.S., an extension of what are known colloquially as motor-voter laws. Such programs, operated through state motor vehicle departments, account for many of the most recent instances of mistaken voter registrations.

That was the case in New Jersey. Sherrill's predecessor, former Gov. Phil Murphy, signed the state's automatic voter registration law in 2018. "By taking this action, we are affirmatively rejecting efforts by President Trump and others who would restrict this fundamental right and attempt to suppress the vote," Murphy, a Democrat, said at the time.

How the years-old registration mistakes surfaced this summer is a mystery. A month or so before Sherrill learned about it, the Republican National Committee and New Jersey Republican Party released letters obtained from county officials that were written on behalf of noncitizens who said they had been registered to vote and wanted to be taken off the rolls.

A spokesman for Murphy said the former governor only heard of the mistake from Sherrill's announcement. Sherrill blamed French vendor Idemia, which provided software to the New Jersey Motor Vehicle Commission. She also cited motor vehicle employees who "knew that this was going on and did nothing to remedy it."

Latrecia Littles-Floyd, the acting chief administrator for the motor vehicle commission at the time of the errors, didn't respond to requests for comment. Idemia denied responsibility, saying that it built the system according to New Jersey's specifications.

Sherrill's administration has hired a New Jersey law firm to conduct an investigation. State Republicans have called for a legislative probe. "We've raised concerns about automatic voter registration from day one," said Republican New Jersey State Sen. Kristin Corrado.

In Oregon, state officials acknowledged in 2024 problems at their state department of motor vehicles that resulted in 1,945 people being registered to vote without proof of eligibility, including some noncitizens. Of the total, 44 cast ballots. Oregon officials learned that staffers at the DMV counter mistakenly picked the wrong option from a drop-down menu, which has since been changed. Officials say they have since added random sampling and audits.

Motor-vehicle divisions "have long been forced into the business of voter registration, which is not their core business," said Stephen Richer, a Republican and former county recorder for Arizona's largest county. "Election administration and voter registration is an add-on thing."

'Love letter'

On July 7, the Justice Department's assistant attorney general for civil rights wrote to chief elections officials in all 50 states, warning that they faced criminal penalties for knowingly allowing noncitizens to remain on voter rolls.

"Got another love letter this morning from the DOJ," Utah Lt. Gov. Deidre Henderson wrote on social media. Henderson, a Republican who serves as chief elections official, has been airing a recent review confirming that 99.72% of Utah's registered voters are verifiably U.S. citizens.

It seems as though no one in the Trump administration "wants to hear, or see, or be shown that we're doing a good job," Henderson said in an interview.

Idaho, another of the Republican-led states sued for its voter lists, also responded tartly to the Justice Department's notice. "Your insinuations of criminal violations of the federal election laws are not well taken," wrote James Craig, a division chief in the state's attorney general's office. "Stop threatening your friends in Idaho."

The Justice Department assistant attorney general, Harmeet Dhillon, said in a statement that her letters were directed at state officials who knowingly failed to act. "This is not about administrative errors," she said.

"The Department is offering technical assistance and legal guidance to any state that wants help ensuring its voter lists are accurate," Dhillon said.

After New Jersey's disclosure, Pennsylvania officials said they quickly retested their automatic voter registration system. The state's auditor general had recently inspected 200,000 voter registration applications and found a single noncitizen among them, said Secretary of the Commonwealth Al Schmidt, a Republican. A clerk had failed to include the status of that person in a driver's license application. "Election integrity requires constant vigilance," Schmidt said.

Washington Secretary of State Steve Hobbs, a Democrat, said that when New Jersey announced its mistaken voter registrations, he immediately asked and learned that his state didn't use the same software vendor that Sherrill blamed.

The number of noncitizens who cast ballots in New Jersey wouldn't have changed the outcome of any election, Sherrill said. Former Vice President Kamala Harris won New Jersey by more than 252,000 votes.

Congressional, state and local elections can be decided by much tighter margins, though rarely as close as two recent House races in Iowa. The 2024 election was decided for the Republican by fewer than 800 votes. In 2020, her margin of victory was six votes.

"The chances of a congressional race being decided by the margin of noncitizen voter participation are less than the chances of getting struck by lightning, but it has become a PR problem for Democrats," said David Wasserman, senior editor and elections analyst at the nonpartisan Cook Political Report.

It isn't just a concern of Democrats. Georgia's Republican Secretary of State Brad Raffensperger said that since 2021, he has conducted several major audits of his state's voter rolls to ensure noncitizens aren't on them.

"It's really important that people have trust in the voter list," said Raffensperger, who has hard-won experience at the center of an electoral storm.

In a phone call after the 2020 presidential election, Trump asked Raffensperger to "find" the nearly 12,000 votes Trump needed to reverse Joe Biden's victory in the state. Raffensperger declined. He lost the GOP primary for governor and will leave office after overseeing his final election.

"We know that we are a bellwether state, we know it's a very competitive state," he said. "What we have been working on is squeezing out any potential areas where people could question the process."

Some state elections officials are more frank about their displeasure with the Trump administration's stance.

"We know that we're doing the best that we can for our voters, and we've got this wild pack of howler monkeys screaming about illegal voters with no evidence and no justification," said Arizona Secretary of State Adrian Fontes, a Democrat from another swing state.