Federal Reserve Gov. Lisa Cook sued President Donald Trump on Thursday and is seeking an injunction from a federal district court to “confirm her status as a member of the Board of Governors.”

The Fed board and its chair, Jerome Powell, are also named as defendants in the case. Cook is seeking a court order to ensure that they do not “effectuate” Trump’s “unprecedented and illegal” attempt to fire her, according to a complaint filed with the U.S. District Court for the District of Columbia.

A hearing in the case is set for Friday.

In the complaint, Cook’s attorneys take issue with Trump’s interpretation of “cause.” The president can fire a Fed governor for cause. However, that standard is left undefined in the Federal Reserve Act, the attorneys asserted Thursday. Trump cited the FRA in a letter dismissing Cook, which the president posted on social media Monday.

“Cause,” when applied to government agencies, is typically limited to a specific finding of “inefficiency, neglect of duty or malfeasance in office” – mirroring Humphrey’s Executor v. U.S. The Supreme Court cited that 1935 case as recently as May, when it upheld Trump’s firing of members of the National Labor Relations Board and Merit Systems Protection Board. However, the court exempted Fed board members from such firings, Cook’s attorneys wrote.

Trump’s dismissal of Cook on Monday “would subvert the Federal Reserve Act” because “an unsubstantiated allegation about private mortgage applications submitted by Governor Cook prior to her Senate confirmation” does not constitute cause, the attorneys wrote.

In his letter, Trump justified Cook’s removal based on a criminal referral that Federal Housing Finance Agency Director Bill Pulte submitted to the Justice Department, alleging Cook obtained two mortgages in 2021, two weeks apart, but claimed in paperwork that each would be used as a principal residence.

“There is sufficient reason to believe you may have made false statements on one or more of your mortgage agreements,” Trump’s letter reads.

“According to President Trump, the ‘may have’ is enough to conclude Governor Cook did something improper, even though the allegation is wholly unrelated to her official duties and does not amount to Section 242 ‘cause,’” Cook’s attorneys wrote Thursday.

Further, Trump’s dismissal of Cook on Monday violated the Fed governor’s Fifth Amendment right to due process and her right to notice and a hearing under the FRA, her attorneys asserted.

The president did not send a copy of the letter to Cook before posting it to social media, nor was she given the chance to respond, the attorneys said.

Likewise, Pulte released the criminal referral letter last week without notifying Cook or giving her the chance to respond to the allegations ahead of time, the attorneys said.

Cook’s complaint lays out Trump’s well-documented history of social-media commentary over Powell’s reluctance to lower interest rates, and notes Cook’s track record of voting in agreement with Powell in Federal Open Market Committee policy-setting meetings.

The complaint also cites a comment Trump made to reporters Tuesday in a Cabinet meeting. “If you did your job properly, we wouldn’t have problems like Lisa Cook,” Trump reportedly said, adding, “I think we have to have lower interest rates, yes.”

“Even if the President had been more careful in obscuring his real justification for targeting Governor Cook, the President’s concocted basis for removal — the unsubstantiated and unproven allegation that Governor Cook ‘potentially’ erred in filling out a mortgage form prior to her Senate confirmation — does not amount to ‘cause’ within the meaning of the FRA and is unsupported by caselaw,” the attorneys wrote.

Trump “does not have the power to unilaterally redefine ‘cause,’” the lawyers added, “and conclude, without evidence, that he has found it.

“Certainly, a policy dispute between the President and a Governor does not constitute ‘cause,’” the attorneys wrote. “Neither does a specious assertion that a one ‘potentially’ committed a crime — one which is unproven, uncharged and unrelated to official conduct.”

The mortgages in question were obtained in 2021; Cook joined the Fed in 2022.

The Fed didn’t escape the complaint unscathed, either. Cook’s attorneys noted that the Fed did not specifically say, in a statement Tuesday, that the central bank would ignore Trump’s move to fire Cook – only that it “will abide by any court decision.”

“This Complaint seeks that decision,” Cook’s attorneys wrote.

“It is clear … the mortgage allegations against [Cook] are pretextual, in order to effectuate her prompt removal and vacate a seat for President Trump to fill and forward his agenda to undermine the independence of the Federal Reserve,” the attorneys wrote.

Trump’s interpretation of “cause,” they added, “has no limiting principle.”

“It would allow him to remove any Federal Reserve Board member with whom he disagrees about policy based on chalked up allegations,” the complaint reads. “That the President says he has found (or created) some basis for removing a Governor does not magically make such a basis grounds for a ‘for cause’ removal under the FRA.”