U.S. President Donald Trump's former campaign chairman has sued Special Counsel Robert Mueller, alleging that the prosecutor overreached by pursuing charges that are unrelated to his mission to investigate alleged Russian interference in the presidential election.
The lawsuit by Paul Manafort, filed in a U.S. district court in Washington on January 3, is the most direct challenge to date to Mueller's legal authority as special counsel.
It comes amid Republican accusations that Mueller's investigative team has shown bias against Trump as it investigates allegations that Trump's campaign team may have coordinated with Russia to influence the outcome of the 2016 election.
Manafort's lawsuit also takes aim at Deputy Attorney General Rod Rosenstein, who is overseeing Mueller's investigation and recently said he was satisfied that the former FBI director was staying within the scope of his authority.
Manafort was indicted in October on charges, including conspiracy to launder money, that stemmed from his lobbying work on behalf of former Ukrainian President Viktor Yanukovych's pro-Russia political party. He has pleaded not guilty.
Manafort is one of four Trump associates -- including former national security adviser Michael Flynn -- to be charged so far in Mueller's investigation.
In his complaint , Manafort alleges that the charges involving "decade-old business dealings" with Yanukovych, who was ousted from office in 2014, are "completely unmoored" from the mandate Mueller was given when he was appointed in May to probe possible ties between the Kremlin and the Trump campaign during the 2016 election.
Manafort was recruited to head Trump's presidential campaign in June 2016, but he stepped down two months later after allegations surfaced in Ukraine that he had been paid more than $12 million by Yanukovych's party.
The lawsuit argues that a paragraph in Rosenstein's order appointing Mueller, which allows him to pursue new matters he comes across during his investigation, is too broad to be permitted under the law that governs U.S. special counsels.
"The Special Counsel's investigation and indictment...far exceeds any lawful authority to investigate links between individuals associated with the Trump campaign and the Russian government," the lawsuit claims.
The lawsuit asks a judge to dismiss all actions brought against Manafort by the special counsel's office and to issue an order narrowing the scope of Mueller's investigation to only matters explicitly laid out in the appointment order.
The complaint also alleges that Rosenstein's order creating the special counsel investigation was overly broad and "arbitrary" and urges a judge to strike it down as an "abuse of discretion."
A spokesman for Mueller's office declined to comment.
A Justice Department spokesman said, "The lawsuit is frivolous, but the defendant is entitled to file whatever he wants."
Manafort acknowledged in his complaint that his political consulting business in Ukraine has been of interest for years to U.S. prosecutors. He said he met voluntarily with Justice Department prosecutors and FBI agents in July 2014, three years before Mueller's appointment, to discuss his "offshore political consulting activities."
He said that during the 2014 interview, he discussed in detail his activities in Ukraine, his relationships with diplomats in Kyiv, and his offshore banking in Cyprus.
But, Manafort said, "those alleged dealings had no connection whatsoever to the 2016 presidential election or even to Donald Trump. Nor were they uncovered in the course of the Special Counsel's probe into President Trump's campaign."