Manafort's attorneys argued in a 17-page lawsuit in federal court in Washington that the department exceeded its legal authority when, in May, acting attorney general Rod J. Rosenstein ordered Mueller to investigate "links and/or coordination" between the Russian government and Trump campaign, as well as "any matters that arose or may arise directly from" that investigation.
The order "purports to grant Mr. Mueller carte blanche to investigate and pursue criminal charges in connection with anything he stumbles across while investigating," no matter how remote from his original charge, Manafort attorneys Kevin M. Downing and Thomas E. Zehnle wrote.
They said the special counsel office's indictment of Manafort alleging he committed fraud, conspiracy and money laundering in secretly lobbying for a Russian-friendly political party in Ukraine focuses not on actions with the Trump campaign in 2016 but private business dealings that began much earlier, adding that he was interviewed by the Justice Department in 2014.
"The actions of DOJ and Mr. Rosenstein in issuing the Appointment Order, and Mr. Mueller's actions pursuant to the authority the Order granted him, were arbitrary, capricious, and not in accordance with the law," they alleged.
A spokesman for the special counsel's office declined to comment.
"The lawsuit is frivolous but the defendant is entitled to file whatever he wants," a Justice Department spokeswoman said.
The lawsuit, assigned to U.S. District Judge Ketanji Brown Jackson, a 2013 Obama appointee, escalates attacks by current and former Trump officials on the legitimacy of the government's investigation into campaign activities.
Manafort, 68, and his longtime deputy, Rick Gates, 45, have pleaded not guilty and remain under home detention awaiting trial on charges including money laundering and fraud.
Their indictment, announced Oct. 30, marked the first criminal charges disclosed in probes into possible Russian influence in U.S. political affairs, which have also swept up former Trump national security adviser Michael Flynn and Trump campaign foreign policy aide George Papadopoulos. Both pleaded guilty to lying to investigators — Flynn about contacts with Russia's ambassador and Papadopoulos about contacts with foreigners claiming high-level connections to them — and are cooperating with investigators.
White-collar criminal defense attorney Jeffrey Jacobovitz said it is not unusual for a defendant to try to question the bounds of a special counsel. But he couldn't recall a single time that approach succeeded in tossing a charge.
Trump, in social media postings after Christmas and New Year's Day, has attacked the special counsel investigation, the Justice Department and the FBI, including the FBI's former director, James B. Comey; former general counsel James Baker; and Deputy Director Andrew McCabe.
Trump, his spokeswoman and his attorney have cast the charges as having nothing to do with the president, who has called the probe a "witch hunt."
Democrats and some Republicans have condemned the strategy of attempting to delegitimize law enforcement, warning that it will only feed the politicization and weakening of key institutions upholding law and order, outcomes Trump supporters say they oppose.
Independent investigations set up by the Justice Department tend to have fairly wide jurisdiction, Jacobovitz said. He noted the charge that led to president Bill Clinton's Senate impeachment trial in 1998 was lying under oath about sexual liaisons with intern Monica S. Lewinsky, in a probe that began over his pre-presidency land deals.
"Look at what Ken Starr was looking at with respect to Bill Clinton and his dealings with Monica Lewinsky, and yet that was not shot down by any courts," Jacobovitz pointed out. "Ken Starr started looking at Whitewater and ended up looking at actions related to Monica Lewinsky."
Devlin Barrett and Amber Phillips contributed to this report.