President Donald Trump’s administration on Wednesday moved quickly to appeal a federal judge’s ruling temporarily blocking Trump from taking the unprecedented step of firing Federal Reserve Governor Lisa Cook.

The Department of Justice filed a brief notice that it was appealing the ruling from late Tuesday by U.S. District Judge Jia Cobb, who said Trump’s claims that Cook committed mortgage fraud prior to taking office were likely not sufficient grounds for her removal.

Trump moved to fire Cook in late August, but the Fed has said she remains in her position. Cobb’s ruling prevents the Fed from following through on Cook’s firing while her lawsuit moves forward.

White House spokesperson Kush Desai on Wednesday, before the appeal was filed, said that Trump had lawfully removed Cook for cause over the mortgage allegations and that “this ruling will not be the last say on the matter.”

Cook, who denies any wrongdoing, sued in late August saying Trump’s claim she engaged in mortgage fraud before she joined the central bank did not give him legal authority to remove her, and was a pretext to fire her for her monetary policy stance.

The case, which will likely end up before the Supreme Court, has ramifications for the Fed’s ability to set interest rates without regard to politicians’ wishes, widely seen as critical to any central bank’s ability to keep inflation under control.

Trump has demanded that the central bank cut rates immediately and aggressively, berating Fed Chair Jerome Powell for his stewardship over monetary policy. The central bank is expected to deliver a rate cut at its Sept. 16-17 policy meeting.

The law that created the Fed says governors may be removed only “for cause,” but does not define the term nor establish procedures for removal. No president has ever removed a Fed governor, and the law has never been tested in court.

Cobb on Tuesday found that the best reading of the law is that it only allows a Fed governor to be removed for misconduct while in office. The mortgage fraud claims against Cook all relate to actions she took prior to her Senate confirmation in 2022.

Trump and William Pulte, the Federal Housing and Finance Agency director appointed by the president, say Cook inaccurately described three separate properties on mortgage applications, which could have allowed her to obtain lower interest rates and tax credits.

The Justice Department has also launched a criminal mortgage fraud probe into Cook and has issued grand jury subpoenas out of both Georgia and Michigan, according to documents seen by Reuters and a source familiar with the matter. Cook has denied wrongdoing.

(Reporting by Daniel Wiessner in Albany, New York; Editing by Alexia Garamfalvi and Andrea Ricci)