ByAlison Durkee,

Forbes Staff.

Supreme Court justices signaled Wednesday they believe President Donald Trump cannot legally fire Federal Reserve Governor Lisa Cook, at least while the case moves forward, as the court held oral arguments in a landmark debate over the Fed’s independence—coming as the Trump administration has launched new attacks against its chair Jerome Powell.

The court heard oral arguments in Trump v. Lisa Cook, a dispute over whether Trump can fire Cook from the Fed’s board because of alleged issues with her personal mortgages, which she denies.

Trump said in August he was firing Cook because of the perceived mortgage issues, but she has remained on the board as courts have sided with her and struck down her termination, and the Supreme Court is considering whether to uphold a lower court order keeping Cook in her role while the litigation moves forward.