Two Democratic US senators have urged California Attorney General Rob Bonta to investigate allegations that federal immigration officers impersonated voters to access California's voter-registration system as part of a programme targeting suspected illegal voters. The request, dated 21 September 2026, was made by Senator Alex Padilla and Senator Adam Schiff, who cited a protected whistleblower disclosure describing operations within the Department of Homeland Security (DHS).

What the Whistleblower Alleged

According to the disclosure, officers from US Citizenship and Immigration Services (USCIS) Fraud Detection and National Security Directorate were directed to use government-held personal information — including driver's licence numbers and partial Social Security Numbers — to log into California's voter-registration website. The internal effort was reportedly called the 'Unlawful Voter Initiative.'

The whistleblower further alleged that officers were assigned daily quotas of 40 cases, leaving roughly 12 minutes per individual review. They were also reportedly required to enter findings into TECS, a federal law-enforcement database, even when officers had reason to doubt the underlying data.

Particularly alarming to the senators was a reference in agency material to a data-enrichment process described as 'supplemental magic.' 'The fact that the DHS data was compiled with something called "supplemental magic" does not provide reassurance,' Padilla and Schiff wrote in their letter to Bonta.

Scope and Risk to Californians

The senators warned that the population examined under the initiative could include US citizens, notably naturalised Americans, and that unreliable determinations could generate erroneous federal law-enforcement records. According to the disclosure, potentially thousands or tens of thousands of California residents could be affected by such records built on uncorroborated information.

'California's voter registration website is clearly intended for the use of voters themselves, and requires the use of sensitive personally identifiable information (PII) to access this voter data,' the senators noted.

How DHS Obtained the Data Remains Unclear

The senators highlighted that the US Department of Justice (DOJ) had previously failed in a legal attempt to compel California to hand over voter data to the Trump administration. That failure, they argued, raises serious questions about the provenance of the information DHS ultimately used — and whether it was collected lawfully.

'As you know, the U.S. Department of Justice has been unsuccessful in its attempt to compel California to provide its voter information to the Trump Administration, raising serious questions about what this data is, how DHS obtained it, and whether they complied with the law in collecting and using this data,' they wrote.

The senators said that agency leaders had reportedly dismissed internal concerns about the legality of the searches and instructed officers to proceed regardless.

Part of a Broader Congressional Push

The California referral is not an isolated action. Padilla and Senate Democratic leader Chuck Schumer had previously called on DHS and USCIS to halt the initiative outright. The two senators also joined 16 other Democratic senators in requesting an independent review by the DHS Inspector General. Together, these efforts signal a coordinated congressional effort to scrutinise the programme ahead of the 2026 midterm elections.

The senators asked Bonta to review the whistleblower disclosure, determine whether California's privacy and voter-information statutes were breached, and consider protective measures for affected residents. All claims in the disclosure remain allegations pending investigation.

Whether California's attorney general will open a formal inquiry — and whether it can reach into federal operations — will be among the key legal questions shaping the next phase of this dispute.