The Department of Justice has revealed new details about how federal investigators flagged more than 20,000 California voters they allege are likely noncitizens, as the Trump administration asks a federal court to prevent their mail ballots from being tabulated until citizenships can be verified.
A lawsuit filed Thursday describes a multistage process involving U.S. Citizenship and Immigration Services (USCIS) and Homeland Security Investigations (HSI), including database matching, third-party software and checks against federal records. The details shed new light on how the Trump administration arrived at a figure California officials strongly dispute.
The federal government provided California officials with a list of more than 20,000 names on Tuesday and gave them 48 hours to review it. After California declined to carry out the requested measures by the DOJ's deadline, the department sued California Secretary of State Shirley Weber and Los Angeles County Registrar-Recorder Dean Logan.
USCIS Checks Voter Rolls Against Its Internal Data
According to the government's complaint, USCIS compares voter-roll information with its internal data to identify possible matches between registered voters and people who may be noncitizens.
The process sorts potential matches into high-, medium- or low-confidence categories. A "high-confidence" match means multiple identifiers support what USCIS considers a strong link between the voter information and its records, the lawsuit says.
The filing acknowledges a potential obstacle in that process: Voter-roll information typically does not contain complete information about a person. USCIS, therefore, uses third-party software to help identify possible matches. Medium- and low-confidence matches can reflect incomplete, outdated or mismatched information, according to the complaint.
The complaint also says the analysis was conducted independently of the federal Systematic Alien Verification for Entitlements (SAVE) program because, to the government's knowledge, California had not submitted voter rolls through that system.
For high-confidence matches, investigators attempt to connect the voter information with an alien number in USCIS systems. They then search for evidence that the person has become a naturalized citizen or may have derived citizenship through their parents or other means.
USCIS also checks State Department records for indicators of citizenship and Social Security Administration records to determine whether an individual has died. A second-level review is conducted before USCIS forwards to HSI the names of voters it assesses with "high confidence" to be likely noncitizens.
HSI then further investigates the names "to determine whether the voters are noncitizens." As part of that process, the agency uses its own analytical platform to address potential information mismatches before sending the data to investigators for further steps, according to the complaint.
USCIS ultimately sent HSI a list of more than 20,000 people it believed were both registered to vote in California and likely noncitizens. After conducting its review, HSI "reasonably believes that around 20,000 noncitizens are registered to vote in California," the lawsuit says.
But the complaint continues to describe those targeted by the requested court order as "likely noncitizens" and asks that their citizenship be verified before their ballots are tabulated.
Asked whether the federal government had definitively established that the roughly 20,000 people are noncitizens, and what gave it sufficient confidence to seek a court order preventing their ballots from being tabulated until their citizenship could be verified, the DOJ referred Newsweek to the complaint. It pointed to the filing's assertion that DHS agencies conducted a "thorough analysis of voter rolls and federal data" and identified thousands of likely noncitizens.
California Questions the List's Accuracy
California officials have challenged both the federal government's conclusions and reliability of its methodology.
In a Thursday letter to the DOJ, Weber said DHS had not provided California with the underlying data or methodology supporting its earlier allegation that more than 190,000 registered voters "may be" noncitizens, despite her office requesting that information in July.
Weber also said she had since been informed that the newer federal list contained approximately 20,000 people statewide, but said it lacked "both the detail and function to be of any investigative use."
"Despite this, and with less than three weeks before the election, you are demanding unprecedented measures that threaten thousands of Californians' right to vote, based on unverifiable information or methodology that you still fail to explain or provide," Weber wrote.
California Attorney General Rob Bonta pointed to DHS' earlier allegation that 190,000 noncitizens were on California's voter rolls, compared with roughly 20,000 at the center of Thursday's case.
"What happened to those 170,000? They just got those wrong," Bonta told the Associated Press (AP).
Asked by Newsweek to explain the difference between the two figures, the DOJ said the 20,000 were people the federal government believes are likely noncitizens who were sent vote-by-mail ballots, and referred further questions about the figures to DHS.
Attorney General Todd Blanche separately said Thursday that the federal agencies had flagged the voters as likely noncitizens and that California had been given an opportunity to correct its records and segregate the associated ballots before the DOJ went to court.
The DOJ did not explain whether the roughly 20,000 at issue now were narrowed from the earlier 190,000 figure. Nor does the difference between the figures by itself establish that 170,000 people were incorrectly flagged, though California officials are citing the change as a reason to question the government's figures.
The California Secretary of State's Office told Newsweek that, because of the pending litigation, it had "no further information" to provide and referred Newsweek to Weber's Thursday response to the DOJ.
Weber also pointed to Nevada, where she said DHS initially alleged that nearly 16,000 potential noncitizens were on the state's voter rolls but ultimately "failed to establish that a single non-citizen was on the voter rolls."
That dispute is particularly relevant because the California complaint itself describes a system in which possible matches can initially carry different degrees of confidence and acknowledges that incomplete, outdated or mismatched information can occur during the matching process.
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What the DOJ Told California to Do
The Tuesday letter that preceded the lawsuit shows the federal government gave California officials until noon Thursday to determine whether any citizens appeared on its list.
For people whose citizenship could not independently be confirmed, the DOJ asked officials to segregate, but not cancel, returned ballots and to stop signature verification or tabulation until citizenship could be determined. It also asked officials not to send ballots to people on the list who had not already received one.
"If you cannot implement this process by then, given the ongoing federal election, the United States will have no choice but to seek emergency relief," acting Deputy Attorney General R. Trent McCotter wrote.
Los Angeles County officials said the list was delivered on a password-protected thumb drive but declined to access it, citing data privacy and information security concerns. The California Secretary of State's office said the password was supplied on a sticky note, according to the AP.
DOJ Asks Court to Halt Ballot Counting
The deadline expired Thursday as voting was already underway ahead of the November 3 midterm elections.
The Justice Department then asked the U.S. District Court for the Central District of California for a preliminary and permanent injunction preventing the state from tabulating vote-by-mail ballots from people identified by the federal government as likely noncitizens until their citizenship could be verified.
The DOJ argues that California's actions conflict with the federal prohibition on noncitizens voting in federal elections and are, therefore, preempted under the Constitution's Supremacy Clause, which establishes that federal law takes precedence when it conflicts with state law. The complaint alleges the state is knowingly facilitating unlawful voting by counting ballots without undertaking the citizenship checks sought by federal officials.
California rejects that characterization. Bonta said Thursday that the administration's demand could run afoul of federal restrictions on systematic voter-roll removals within 90 days of an election.
Governor Gavin Newsom also condemned the lawsuit Thursday, calling it a "sad, desperate attempt" by the Trump administration to suppress California voters less than three weeks before Election Day. He said California would continue to conduct its elections despite the federal challenge.
Weber raised a separate legal objection in her Thursday letter, saying she was concerned that the DOJ's demand may violate an October 9 federal court order. She said the order had vacated a DOJ policy involving comparisons of state voter-roll information with federal databases and demands that states remove voters based on the results. "It appears that your letter may utilize a policy that a federal court has already deemed unlawful," Weber wrote.
Election law professor Rick Hasen of the University of California, Los Angeles, also told Reuters that the lawsuit would likely face legal hurdles, saying he did not see federal authority for the government to directly instruct states which ballots they can send or count.
The Trump administration has made noncitizen voting a major focus ahead of the midterms, though documented cases remain rare. Reuters reported that an investigation published in July identified 129 people prosecuted for noncitizen voting since the federal statute criminalizing it was enacted in 1996.
Thursday's lawsuit puts not only those 20,000 California ballots before a federal court, but also the administration's method of flagging the voters. The complaint provides substantially more detail about how investigators compiled the list, while the central dispute remains whether that process has established enough about those voters' citizenship to justify halting tabulation of their ballots until such citizenship can be verified.
Newsweek’s reporters and editors used Martyn, our AI assistant, to produce this story. Learn more about Martyn here. Contact Newsweek editors on this story: Edward T. Cummins