A federal judge has ruled that the Trump administration could soon begin sharing specific Medicaid data regarding suspected undocumented immigrants with Immigration and Customs Enforcement (ICE). This decision was handed down by U.S. District Judge Vince Chhabria, who stated that the sharing of details such as “citizenship and immigration status, address, phone number, date of birth, and Medicaid ID” is “clearly authorized by law.”

In a comprehensive seven-page order issued on Monday, Judge Chhabria noted that both the Department of Homeland Security (DHS) and the Department of Health and Human Services (HHS) had adequately justified their decision to break from previous policies. These agencies had traditionally not used Medicaid data for immigration enforcement.

The agencies argued that this policy shift aligns with multiple executive orders from President Donald Trump. These orders directed federal agencies to enforce immigration laws more rigorously and enhance border security, as outlined in their explanations.

This ruling marks a significant victory for the Trump administration’s immigration enforcement efforts. Starting January 6, DHS and HHS will be authorized to share specific data about individuals on public health insurance suspected of being undocumented with ICE, thus providing a new tool for tracking and potentially detaining those believed to be in the U.S. illegally. However, the scope of shared data remains restricted.

Judge Chhabria, appointed by President Barack Obama, made this decision while responding to a preliminary injunction motion filed by California Attorney General Rob Bonta. The motion, supported by California and 21 other states, sought to prevent the dissemination of additional personal information. Judge Chhabria granted this injunction, thereby limiting the extent of data sharing.

Bonta and the other states filed a lawsuit on July 1, targeting HHS’s Centers for Medicare & Medicaid Services (CMS) handing over of “a trove of individuals’ protected health data” to other federal agencies, including DHS, “without their consent.” Chhabria proceeded to bar the administration from sharing Medicaid data “obtained from the plaintiff states for immigration enforcement purpose” while the case played out and the agencies explained their actions.

The judge determined the Trump administration may not share information beyond “basic biographical, location, and contact” because the federal government’s “new policies are totally unclear about what that information would be, why it would be needed for immigration enforcement purposes, and what the risks of sharing it with DHS would be.”

Such reasoning would rule out the government acting “arbitrarily” in violation of the Administrative Procedure Act, the statute governing federal agencies’ behavior. And so while Chhabria opined in the recent order that DHS and HHS adequately explained their actions, allowing for the sharing of certain data, he also found that significant questions remain.

The judge wrote, at length:

Beyond the basic information discussed above, the policies are totally unclear and do not appear to be the product of a coherent decisionmaking process. It is unclear (1) whether DHS may obtain from HHS any information relevant to any proceedings beyond criminal immigration investigations or civil enforcement actions; (2) what data DHS is authorized to obtain from HHS on a “case-by-case” basis and what factors are considered in such inquiries; and (3) whether DHS may request any data from HHS about citizens or lawful permanent residents, including members of mixed-status households. It’s even an open question whether the policies would allow HHS to share sensitive medical information about Medicaid patients with DHS— information that’s difficult to imagine the agency needing for any legitimate purpose. Furthermore, neither the ICE Memo nor the CMS Notice address why a more narrowly tailored policy, focused on the basic biographical information discussed above, would not suffice for immigration enforcement purposes.

Chhabria’s order consequently narrowed the Medicaid information that the administration can share.

“To the extent that such basic biographical, contact, or location information about unlawfully present aliens is not severable from other information that DHS and ICE are not entitled to obtain (e.g., information about lawful permanent residents or citizens, sensitive health records), HHS or CMS may not share it,” he wrote. If DHS requests that additional information be made available to them, they must approach the court.

A spokesperson for the California Department of Justice told Politico after the ruling that individuals signed up for the state’s health care program under the belief their personal information would be used solely for their health care.

“The Trump Administration’s effort to use Medicaid data for immigration enforcement is a violation of their trust and will lead to fewer people seeking vital healthcare,” the agency said in a statement.

DHS spokesperson Tricia McLaughlin, on the other hand, called the court ruling “a victory for the rule of law and American taxpayers.”