The U.S. attorney general wields vast power over the immigration courts, and a labor union for judges who run those courts is headed for an existential showdown Tuesday with its members’ employer: the Department of Justice.

The friction between the National Association of Immigration Judges and the Justice Department heated up when Jeff Sessions was attorney general. In 2018, the union called on Congress to make immigration courts independent from the Justice Department.

Then in August 2019, the Justice Department moved to decertify the union. Documents show that the Justice Department thinks work done by immigration judges has evolved, they are now actually managers under federal law, and this disqualifies the judges from forming a union.

Both sides will have the chance to make their case at a hearing in Washington, D.C., held by the Federal Labor Relations Authority.