A federal appeals court on Wednesday temporarily blocked a California law that would have required federal immigration agents to clearly identify themselves.

A three-judge panel of the 9th Circuit Court of Appeals unanimously granted a preliminary injunction in favor of the Trump administration, saying it was likely to succeed in its case challenging the law. Two of the three judges were appointed by President Donald Trump.

Gov. Gavin Newsom signed the bill into law in September. The legislation would have required all law enforcement officers operating in California to make their badge number and the agency they work for visible while on duty. The Trump administration sued the state in November, claiming that officers should have the choice of whether to make their identities visible to provide an “extra layer of security.”

Initially, the lawsuit also targeted a separate law last year that would have banned law enforcement officers from wearing face coverings while on duty. That law was blocked earlier this year by a federal judge who said that because the ban did not apply to local authorities, it unfairly discriminated against the federal government.

In its lawsuit against the California identification mandate, the Trump administration alleged that California was trying to regulate the federal government, and therefore violated the Constitution’s Supremacy Clause. The appellate court agreed.

“The Supremacy Clause prohibits States from enacting a law that directly regulates federal operations even if the law regulates state operations in the same manner,” Judge Mark J. Bennett, a Trump appointee to the appellate court, wrote in the opinion.

Newsom signed the legislation in response to Trump’s crackdown on undocumented immigrants, a campaign launched last summer with raids in Los Angeles.

Los Angeles County Board of Supervisors officials said in a February report that the raids caused more than $1 billion in lost productivity, wages and sales because businesses were shuttered amid the federal action and subsequent protests.