Cantwell Condemns Illegal IRS-ICE Data Sharing; Court Issues Preliminary Injunction on Section 6103

Sen. Maria Cantwell and a bicameral group of lawmakers asked the U.S. Court of Appeals for the First Circuit on August 6, 2026, to preserve a court order blocking IRS-ICE data sharing. They argue that the disclosure of taxpayer addresses to immigration authorities violated federal tax-confidentiality rules.

Cantwell, a Washington Democrat and ranking member of the Senate Commerce Committee, led nine other senators and 74 House members in filing an amicus brief. The lawmakers support the Community Economic Development Center of Southeastern Massachusetts, which is challenging the data exchange with the IRS.

The case concerns the Internal Revenue Code section 6103, which generally restricts the disclosure of tax-return information. The brief says Congress has rejected earlier proposals that would have allowed immigration-enforcement agencies to use return information.

The Trump administration appealed after U.S. District Judge Indira Talwani blocked the agreement. The lawmakers now want the First Circuit to keep that preliminary injunction in place while the appeal proceeds.

Cantwell said the arrangement disregarded both the statute and its legislative history.

“The data sharing at issue in this case by the [IRS] and [ICE] violates the express terms of the statute and ignores its history. It would also compromise taxpayer privacy and raise the possibility of grave consequences for individuals misidentified by ICE.”

The dispute involves addresses, not the complete contents of taxpayer returns. Its reach has nevertheless been broad.

ICE sought addresses for about 1.28 million people

In June 2025, ICE asked the IRS for the last known addresses of approximately 1.28 million individuals as part of an immigration-enforcement campaign. The IRS later supplied addresses for 47,289 people on August 7, 2025.

A Treasury Inspector General for Tax Administration report found problems with the agency’s automated matching system. The system sometimes treated incomplete or inaccurate addresses as valid, including entries showing “00000” or jail-facility locations.

A federal ruling cited in the litigation found that the IRS violated Section 6103 “approximately 42,695 times” by disclosing information without verifying whether ICE requests satisfied statutory requirements for criminal investigations. The findings have intensified scrutiny of how the agencies reviewed and matched the records.

Dottie Romo, the IRS chief risk and control officer, acknowledged in a court declaration that the data-sharing process was flawed. The officials involved included Scott Bessent, the acting IRS commissioner and Treasury secretary; Frank Bisignano, the IRS chief executive officer; Kristi Noem, the secretary of Homeland Security; and Todd Lyons, the acting ICE director.

Lawmakers warn that errors could expose citizens

Sen. Ron Wyden, the Oregon Democrat who serves as ranking member of the Senate Finance Committee, called for criminal accountability in a statement on June 8, 2026.

“ICE is a lawless organization that should never have come anywhere near taxpayer data. Those responsible for violating the law should face prosecution.”

Sen. Alex Padilla, the California Democrat who is ranking member of the Senate Judiciary Immigration Subcommittee, warned that the matching failures may have identified large numbers of taxpayers incorrectly. He said those errors could include U.S. citizens and expose them to possible deportation.

The Community Economic Development Center said the policy also affected people before any enforcement encounter. Applications for Individual Taxpayer Identification Numbers at its Massachusetts office fell 74% in 2026, the group said, as people feared that filing taxes could alert ICE.

ITINs allow people who cannot obtain Social Security numbers to meet tax obligations. The agreement reversed decades of IRS policy protecting the confidentiality of ITIN filers, according to the litigation materials.

A 2025 agreement triggered the court challenge

The dispute began with an April 2025 Memorandum of Understanding between the IRS and the Department of Homeland Security. The arrangement formed part of an administration-wide push to use federal records in mass-deportation efforts.

The policy change followed the resignation of the then-acting IRS commissioner in early 2025. Advocacy groups, including the Asian Law Caucus and Centro de Trabajadores Unidos, then brought litigation challenging the arrangement.

The lawmakers’ brief backs the Community Economic Development Center’s case, styled Community Economic Development Center of Southeastern Massachusetts v. Bessent. The First Circuit is considering the administration’s challenge to Talwani’s order.

The dispute also raises a broader tax-compliance concern. Lawmakers say using tax information for immigration enforcement could discourage residents from entering the legal tax system and threaten federal revenue.

California joins the fight over the data exchange

California Attorney General Rob Bonta filed a separate amicus brief on August 3, 2026, with a coalition of 17 states. That filing also supports keeping the lower-court block on IRS disclosures to ICE.

Cantwell and the Senate Finance Committee separately voted July 30 on the Taxpayer Assistance and Service Act. An amendment that would have prevented the IRS from granting audit immunity to high-ranking officials was voted down, adding to the congressional debate over agency accountability.

The First Circuit appeal remains pending. If the court leaves the order intact, the restrictions will continue during the covered litigation, but the final legal status of the policy will depend on the appeal and any later proceedings.

This article provides general information and is not legal advice. Consult a qualified immigration attorney about your specific case.