Former FBI Director James Comey is contesting the legitimacy of President Donald Trump’s designation of his personal counsel, Lindsey Halligan, as a U.S. attorney.

Comey’s action evaluates the viability of Trump’s political payback strategy, executed through the appointment of loyalist prosecutors, in a judicial context, Axios noted.

“James Comey, by counsel, will file his motion to dismiss challenging the lawfulness of the appointment of the United States Attorney for the Eastern District of Virginia,” Comey’s attorneys wrote.

Comey’s filing warns the court that it should prepare for an “out-of-district judge” to preside over his motion.

Comey entered a plea of not guilty last week to allegations of perjury before Congress during his testimony in 2020.

In 2017, Trump dismissed Comey following a confrontation on the FBI’s inquiry into possible connections between the president’s campaign and Russia. Trump appointed Halligan last month following the resignation of former U.S. Attorney Erik Siebert.

Since assuming office, Halligan has indicted both James and Comey. A White House spokesperson informed Axios that President Trump possesses “full confidence” in Halligan.