Prosecutors, in a motion Friday to federal District Court Judge Amy Berman Jackson, said Manafort is using the lawsuit as a way to have his money-laundering indictment thrown out. The suit filed Jan. 3 said Mueller overstepped his mandate by receiving "carte blanche" to pursue "any matters that arose or may arise directly from the investigation" into Russian meddling in the 2016 election and possible collusion by Trump's campaign staff.
"The appointment of the special counsel was squarely within the acting attorney general's authority and consistent with the department's special counsel regulations," the motion said. "And the special counsel is properly operating within the scope of his authority, including with respect to Manafort's ongoing criminal prosecution."
The prosecutors said the complaint is "both implausible and irrelevant."
"The relief sought in the complaint includes a request for 'an order and judgment setting aside the appointment order and declaring it invalid,' '' the motion said. "To be sure, the complaint does not spell out what it would mean to 'set aside' all actions that the special counsel has taken against Manafort. But any plausible meaning would surely include 'setting aside' the indictment."
In the filing, prosecutors cited the Dec. 13 congressional testimony of Deputy Attorney General Rod Rosenstein, who oversees Mueller's work: "I'm properly exercising my oversight responsibilities, and so I can assure you that the special counsel is conducting himself consistently with our understanding about the scope of his investigation," Rosenstein testified.
Rosenstein has been Mueller's boss after Attorney General Jeff Sessions recused himself from the investigation because he was an adviser to Trump during the presidential campaign and met with Russian ambassador Sergey Kislyak.
According to prosecutors, Manafort misinterpreted Mueller's appointment as allowing him to investigate crimes "uncovered for the very first time during his investigation." They said he can prosecute crimes the Justice Department knew about.
In the indictment on Oct. 31, Manafort and a longtime associate, Rick Gates, are accused of failing to register as agents in the United States for political consulting they did for Ukraine and pro-Russian politicians. They also allegedly conspired to launder millions of dollars and hiding offshore bank accounts.
They have pleaded not guilty and a trial date hasn't been set.
"This lawsuit plainly seeks to interfere with Manafort's ongoing criminal prosecution," Justice Department attorneys said.
The Justice Department motion came hours after the release of a memo by Republicans on the House Intelligence Committee alleging bias by the FBI and Justice Department officials involved in the Russia probe.