US federal judge tosses Paul Manafort's lawsuit against Robert Mueller authority

Former Trump campaign manager Paul Manafort (R) arrives at the Albert V. Bryan US Courthouse for an arraignment hearing as a protester holds up a sign, March 8, 2018 in Alexandria, Virginia. (Photo by AFP)

A US federal judge has tossed out a lawsuit filed by President Donald Trump's former campaign manager seeking to challenge the authority of Special Counsel Robert Mueller in the ongoing Russia investigation.

The decision by US District Judge Amy Berman Jackson was a blow to Paul Manafort's defense against numerous charges brought by Mueller and a rejection of his attempt to use a civil lawsuit to foil his criminal prosecution.

In her 24-page ruling, Jackson rejected Manafort's request for an order protecting him from future prosecutions by Mueller's investigators.

Manafort filed the civil action in January, claiming that Mueller had “acted beyond the scope of his authority” and his investigation was not permitted under Justice Department regulations.

It was the first of Manafort's challenges to the counsel’s authority.

"A civil case is 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," wrote Jackson, who was appointed by former President Barack Obama.

"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 defect in the prosecution in the trial court or on direct appeal,” she noted.

"Therefore, the Court finds that this civil complaint must be dismissed."

The charges against Trump’s former aide surround his lobbying work for pro-Russian political parties in Ukraine.

Mueller has charged Manafort with conspiracy, money-laundering, and acting as an unregistered foreign agent for the Ukrainian government, among other charges.

Manafort’s business associate, Richard Gates, pleaded guilty earlier this year. However, Manafort has pleaded not guilty to the charges against him.

Court documents show that Manafort was interviewed by FBI agents twice when he worked as a consultant in Ukraine.

Manafort and Gates were among the first to be charged as part of Mueller's ongoing investigation into whether the Trump presidential campaign colluded with Russia to influence the 2016 US election.