SAN DIEGO (AP) — A federal agency Tuesday ruled to strip the collective bargaining powers of a national union representing more than 450 U.S. immigration judges that has been a vocal critic of the Trump administration’s policies.

The Federal Labor Relations Authority sided with the U.S. Justice Department in saying that immigration judges hold a position akin to management and therefore do not have a right to collective bargaining.

Judge A. Ashley Tabaddor, president of the National Association of Immigration Judges, called the decision retaliation by the government.

The union has been a major voice for more independence from the Justice Department, which oversees U.S. immigration courts.

While immigration judges wear black robes and preside over non-jury proceedings, they are considered federal attorneys with the Justice Department and can be removed from their positions by the U.S. Attorney General.

In contrast, federal judges who oversee criminal and civil matters are more autonomous because they are appointed for life and work for the independent judicial system.

The union's leaders have been outspoken critics of a broken immigration court system with a backlog that has ballooned to more than 1.2 million cases under President Donald Trump. It has also resisted a mandate from the administration requiring immigration judges to complete 700 cases annually to meet job performance standards.

Four months ago, the union filed a lawsuit against the Justice Department over a new policy that prohibited them from speaking publicly about immigration law or even court policies. Judges who violate the policy can face reprimands or be suspended or removed.

The judges under previous administrations were allowed to speak in their personal capacities on issues relating to immigration if they made it clear that they were not speaking on behalf of the Justice Department or the court system.

The union vowed to fight Tuesday's decision though it was unclear what legal options it has. The labor relations authority did not immediately respond to a request for comment from The Associated Press nor did the Executive Office for Immigration Review, the agency under the Justice Department that runs the courts.

Tabbador said the union will continue to support immigration judges and pointed out in a letter Tuesday to its members that they still have protections as federal government employees.

But she told AP “it’s a profound impact. It’s unprecedented. We anticipate the agency is going to fully attempt to muzzle judges from being able to speak publicly.”

The Federal Labor Relations Authority is an independent agency of the U.S. government that governs labor relations between the federal government and its employees.