New Jersey Democratic Gov. Mikie Sherrill’s recent announcement of 6,600 ineligible voters found on the state’s rolls is only the latest in a decades-long string of cases involving noncitizens registered to vote in U.S. elections, records show.

Sherrill said that the ineligible voters were registered due to a "serious software error" in New Jersey’s Motor Vehicle System. Her announcement came within a week of a major address from President Donald Trump in which he warned that digital election interference posed a "cyber threat aimed at the very heart of our democracy."

While New Jersey is the latest documented failure, it is not an isolated anomaly. New Jersey's error adds to a 25-year record of state reviews, software failures and prosecutions that found noncitizens on voter rolls and, in some documented cases, casting ballots. Experts say the episodes establish a recurring vulnerability. However, due to the lack of a national standard for identifying and reporting errors, reviews are sporadic and use different methods, making it impossible to determine how widespread the problem truly is.

"It's a major vulnerability," Jason Snead, executive director of the conservative think tank the Honest Elections Project, told Fox News Digital. "And we have seen just within the last couple of years many states that have checked their voter rolls and found non-citizens on them … So, this is a big problem."

According to New Jersey’s preliminary findings, fewer than 400 individuals who were improperly registered ended up voting. Sherrill said they lived all across the state and mostly lacked a party affiliation, though there were some registered as Democrats or Republicans.

Fox News Digital reached out to the New Jersey Secretary of State Division of Elections, state Attorney General Dale Caldwell and the chairs of several key legislative elections oversight committees for clarification on which elections the 400 ineligible voters participated in and to request details on the state’s auditing protocols. Fox News Digital did not receive a response from any of the state officials mentioned above.

Snead explained that though states are required by law to ensure their voter rolls are up to date and accurate, there is no uniform federal requirement for a state to disclose its findings. He said that this has led to differences across states in how the law is enforced and how errors are reported.

"There are federal requirements to maintain clean and accurate voter rolls. And of course, it is a federal crime for a noncitizen to register and to vote, but there's no requirement that a state report how many non-citizens that they have found up to the federal government. That's entirely a state law question," he explained.

He argued that problems involving noncitizen voting are greater in blue states due to policies he said make it easier to cheat.

"When you look at the policies that are pushed in blue states by the left, things like automatic voter registration, giving drivers licenses to illegal aliens, banning voter identification laws, no proof of citizenship to vote on and on and, this is the inevitable outcome of all of those policies," said Snead, adding, "This is not the first time that we've seen a state with automatic voter registration add potential non-citizens to the rolls."

After the president’s speech, Homeland Security Secretary Markwayne Mullin released a statement announcing that preliminary DHS reviews of state records found "as many as" 250,000 noncitizens registered to vote in four states: 35,152 in New Jersey, 190,832 in California, 15,903 in Nevada and 14,576 in Pennsylvania.

Fox News Digital reached out to DHS for clarification on its preliminary findings. However, DHS did not answer Fox News Digital’s questions and instead sent a statement from Mullin reiterating the number.

In the statement, Mullin emphasized to Fox News Digital that "this shouldn’t be a red or blue state issue: ONLY Americans should elect American leaders." He added that "we’ve put these governors on notice. States must work with us to ensure free, fair, and honest elections."

Charles Stewart III, a professor of political science specializing in elections at MIT, explained that the controlling federal law governing voter registration, the National Voter Registration Act (NVRA), is "silent on the issue of noncitizens on the roll."

He told Fox News Digital that because "this was not an issue in the early 1990s … one of the ambiguities right now and controversies is over precisely what sort of obligations states have to audit their rolls for noncitizens."

"This is really at the crux of the matter and two of President Trump's executive orders. It's the crux of the matter in the Save America Act. It is the crux to the matter in the current efforts, well, back to the executive orders and a lot of the lawsuits. And the states are pointing out, when being pressed by the federal government, that yes, it is illegal for noncitizens to vote, for sure, and states should have an obligation to make sure noncitizens are not registering, but there is no federal law that compels states to do investigations, nor is there a federal law to compel them to report.

Meanwhile, states that have published review results have reported concerning findings. Besides New Jersey, state reviews conducted since 2020 have found evidence of significant numbers of noncitizens registered to vote in Louisiana, Iowa, Michigan, Ohio and Illinois, a Fox News Digital review found.

Earlier this year, Louisiana Secretary of State said that using the federal Systematic Alien Verification for Entitlements (SAVE) database, which was rolled out by the Trump administration last year, the state identified 403 noncitizens on its voter rolls, 83 of whom had voted in elections, American Press reported.

In 2025, an audit by the Iowa secretary of state confirmed that 277 noncitizens were registered to vote and that 35 successfully voted in the 2024 election while five attempted to vote but were rejected.

The same year, the Michigan Department of State published its findings from a review of the 2024 election, which it said proved that "credible cases of noncitizens casting a ballot in Michigan elections are extremely rare." The review found that 15 people, who it said "appear to be non-U.S. citizens," cast a ballot in the election. Additionally, the department identified a Chinese national who allegedly voted illegally.

The Ohio Secretary of State's Office announced in 2024 and 2021 that it had identified 597 and 117 apparent noncitizen voter registrations, respectively, and referred the cases for further investigation.

According to findings cited in Illinois legislation and testimony by secretary of state officials before the general assembly, a programming error in the state's automatic voter registration system allowed the records of 574 people who identified themselves as noncitizens to be transmitted to election officials between 2018 and 2019.

Further, officials in Pennsylvania, Texas, Maryland, Colorado, Florida and North Carolina have also reported cases of noncitizens being registered to vote as far back as 2000.

In testimony given to the Pennsylvania House State Government Committee in 2017, then elections commissioner Jonathan Marks revealed that the state had found 1,160 records of apparent noncitizens who self-reported and canceled. Marks said that a deeper analysis of the years 2000 through 2017 found 544 ballots were cast by the identified registrants.

In Texas, authorities discovered a resident alien named Rosa Ortega registered in 2002 and voted five times from 2004 through 2014, according to Attorney General Ken Paxton.

In another case, a Ghanaian national named Michael Nana Baako registered to vote in Maryland, swearing that he was a U.S. citizen in 2005 and subsequently voted in 10 federal elections between 2006 and 2018, according to the DOJ.

A 2012 report by the Colorado Department of State revealed that the state identified 3,903 registered voters whose citizenship status was "in question." An additional 430 Colorado voters were found to have identified themselves as ineligible to vote because of citizenship requirements.

The report noted that in Colorado "no proof is required to validate the status indicated on a registration form." It said that individuals can register to vote at a driver’s license office, state public assistance office, county office, private voter registration drive, or even online, none of which verify citizenship.

Three reviews conducted by the Florida Department of State for the years between 2013 and 2017 identified 821 noncitizen registrations and 126 people with voting histories.

Meanwhile, a 2017 state audit in North Carolina concluded that 41 legal-status noncitizens cast ballots.

Fox News Digital also reached out to the Justice Department to ask how many individuals the agency has charged with noncitizen voting or unlawful voter registration since 2000. However, a spokesperson for the DOJ did not offer specifics. Instead, the spokesperson sent Fox News Digital a statement assuring that the department’s Civil Rights Division "is investigating and will keep pressing states to clean their rolls" and is "prosecuting cases where the law and evidence support it."

The DOJ spokesperson reiterated that "it is illegal for any noncitizen to vote in a federal election" and that "every unlawful vote dilutes the voice of American citizens."

"Whether or not a case is prosecutable doesn't change the fact that the wrongful vote happened — DHS found over 250,000 likely noncitizens on voter rolls nationwide, and New Jersey's own Governor confirmed 400 noncitizens voted there," the spokesperson said.

"The fact of the matter is that election after election after election after election happened and no one did anything about it," remarked Gene Hamilton, president of America First Legal.

He pointed to a letter sent by the DOJ’s Civil Rights Division to election officials in all 50 states which he said, "reminded them of their obligations and the possibility of legal consequences for not taking action."

Since President Donald Trump's return to office, the Civil Rights Division has filed lawsuits against 30 states and the District of Columbia seeking to compel the production of full voter registration lists under the NVRA, according to the Brennan Center for Justice.

"There are ways to fix it," said Hamilton. "It's just a matter of desire."