A federal judge expressed doubts Wednesday about a lawsuit brought by Paul Manafort challenging special counsel Robert S. Mueller III’s criminal probe of Russian interference in 2016 U.S. elections.

During a 90-minute hearing in Washington, Manafort’s defense team retreated from requests that the court void Mueller’s appointment and dismiss criminal charges already brought in the District and Virginia against President Trump’s former presidential campaign chairman.

But Manafort’s lawyers asked the court to bar Mueller from bringing future charges, saying a provision authorizing the special counsel to investigate “any matters that arose or may arise directly from” its probe of possible collusion between Trump officials and the Russian government is an abuse of the Justice Department’s legal authority.

Manafort’s attorneys argue the provision in the May order appointing Mueller is so broad that it violates the department regulation governing the special counsel, which they argued required a “specific factual description” of the matter to be investigated.

U.S. District Judge Amy Berman Jackson of Washington made clear her skepticism as she questioned Manafort attorney Kevin M. Downing.

How, she asked, did he expect a court to act against charges that have not yet been brought, and how could he know that Manafort would be prosecuted lawfully or unlawfully?

“You have to wait until the harm is crystallized,” Jackson said at one point. “You’re saying, ‘Stop something’ that I don’t even know is going to happen. I don’t understand what’s left to your case.”

She added, “Do you have a single legal case that says that a subject of an ongoing [criminal] investigation” can sue under the law cited by Manafort that governs how federal agencies issue regulations, the Administrative Procedure Act?

Downing said that he did not, and also said that he expected Jackson to ignore a provision in the special counsel regulation that bars private parties from going to court to seek to enforce internal management rules.

Downing argued that more explicit authorization is required “to keep a special counsel from doing whatever he wants to,” citing a history of alleged abuses of power by independent prosecutors.

Forcing defendants to try to dismiss counts case-by-case and “chasing indictments” jurisdiction by jurisdiction would force criminal defendants into a game of “whack-a-mole” that no individual could win against the resources of the government, Downing said.

Manafort, 69, has pleaded not guilty to felony charges related to his work as an international political consultant in Ukraine before joining Trump’s campaign in March 2016. He resigned from the campaign in August 2016.

Manafort separately has moved to dismiss criminal charges in the District ahead of a scheduled September trial date and in federal court in Alexandria, where he faces trial July 10.

Wednesday’s hearing did not touch on what Jackson called “a little bit of the elephant in the room,” over a District court filing late Monday by prosecutors in Manafort’s criminal case. The filing included a partly redacted memo that revealed Deputy Attorney General Rodney J. Rosenstein authorized Mueller to pursue allegations that Manafort colluded with Russia in 2016. Manafort has not been charged with any crimes connected to the presidential race.

Downing said Manafort’s defense had “major issues” with the added authorization, saying it came after a search warrant had already been executed on Manafort’s home.

The judge did not say when she would rule on the civil case.