A federal judge on Friday dismissed former Trump campaign chairman Paul Manafort's lawsuit challenging special counsel Robert Mueller's power, ruling that his civil case was not the “appropriate vehicle for taking issue with what a prosecutor has done in the past or where he might be headed in the future.”

Manafort sued the U.S. Department of Justice in January, arguing that the special counsel had gone beyond its mandate of investigating Russian interference in the 2016 presidential election by probing his overseas lobbying work. The lawsuit, filed in Washington federal district court, came three months after Manafort and his longtime associate Rick Gates were indicted on criminal charges related to their past lobbying work for Ukraine.

Manafort's defense lawyers narrowed their civil complaint to ask U.S. District Judge Amy Berman Jackson of the District of Columbia to enjoin any future actions under Mueller's appointment order leading the Russia investigation. That narrowing wasn't enough for the judge.

“It is a sound and well-established principle that a court should not exercise its equitable powers to interfere with or enjoin an ongoing criminal investigation when the defendant will have the opportunity to challenge any defects in the prosecution in the trial or on direct appeal,” Jackson wrote on Friday. “Therefore, the court finds that this civil complaint must be dismissed.”

Jackson did not reach the merits of Manafort's claim about the legitimacy of Mueller's appointment, saying that any such attack could be addressed in Manafort's criminal cases. Jackson said Manafort has an “adequate remedy at law in the form of his pending motions to dismiss or future motions to dismiss.”

Jackson's decision was not unexpected. She appeared skeptical of Manafort's challenge during a hearing earlier this month in Washington federal court. Manafort defense lawyer, Kevin Downing, a former Miller & Chevalier partner, argued during that hearing that an injunction was necessary to guard against the possibility of future prosecutions in additional jurisdictions. “Chasing indictment after indictment is not an adequate remedy,” Downing said.

The hearing came just days after Mueller's team defended its authority by releasing a copy, with portions blacked-out, of a classified Justice Department memorandum issued in August 2017.

In the memo, Deputy Attorney General Rod Rosenstein specifically stated that it was within the special counsel's scope to investigate payments Manafort received from the Ukrainian government before and during the tenure of the country's Russia-backed former president, Viktor Yanukovych.

Rosenstein took over the special counsel investigation last year after U.S. Attorney General Jeff Sessions recused himself from matters related to the President Donald Trump campaign. In recent weeks, speculation has swirled about whether that recusal extends to the Justice Department's investigation into payments Trump's longtime personal lawyer, Michael Cohen, made to two women who claim to have had affairs with the president.

Appearing before a Senate panel on Wednesday, Sessions deflected questions about whether he had recused himself from the investigation of Cohen, saying he had “given it some thought” and determined Justice Department policy prohibited him from answering definitively.

Jackson's opinion is posted in full below:

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