U.S. District Judge Amy Berman Jackson has questioned the scope of the authority granted Special Counsel Robert Mueller by Deputy Attorney General Rod Rosenstein.

During a hearing in one of the criminal cases against former Trump campaign chairman Paul Manafort, Judge Jackson cast doubt upon the directive appointing Mueller and its broad-brush approach to the investigation. Mueller’s directive allows him to probe the alleged connections between Russia and the 2016 Trump presidential campaign, as well as issues that “may arise” in the course of that investigation.

But Justice Department regulations mandate that a directive must describe a “specific factual matter” to the special counsel. “That’s a fair point,” Jackson said when the point was raised by Manafort’s lead defense attorney, Kevin Downing. “I don’t think that, as good as he is, that the deputy attorney general can see into the future.”

It does not, however, seem likely that even questioning the breadth of Mueller’s authority will do anything to save Manafort from his reckoning. He faces 23 counts across two indictments in both Washington and Virgina, including failure to register as an agent of Ukraine, money laundering, bank fraud, tax evasion, and failing to report foreign bank accounts.

But Manafort’s lawyers continue to push the issue, trying to invalidate the investigation if they cannot answer the charges themselves. They contend that Mueller has gone even further than was authorized by Rosenstein, and that even his authorization was against Justice Department rules.

“I don’t know how they can violate these regulations and we can still be here and it doesn’t matter,” Downing said. “It doesn’t make any sense.”

Senior Justice Department attorney Michael Dreeben disagrees. Of the order, he said, “It’s not a blank check. It’s not carte blanche,” and it “reflects confirmation of what was within our scope at the time of our appointment.”

For her part, Jackson has issued no official judgment regarding the issue of Mueller’s authority. She also did not seem convinced that the issue had resulted in any undue harm to Manafort himself. She believes it likely that a closer look at Manafort’s allegedly dubious business dealings was a part of the larger investigation by the time Mueller was appointed. Further, that Manafort’s ties to Ukraine qualified under “links” between the Trump campaign and the Russian government.