A divided federal appeals court ordered the dismissal of the criminal case against President Donald Trump's former national security adviser Michael Flynn.

Michael Flynn, President Donald Trump's former national security adviser, departs a federal courthouse after a hearing, Monday, June 24, 2019 in Washington.
Michael Flynn, President Donald Trump's former national security adviser, departs a federal courthouse after a hearing, Monday, June 24, 2019 in Washington. (AP)

Democrats in Congress have accused the Trump administration of politicising the Department of Justice after the federal appeals court ordered criminal charges dropped against former White House national security advisor Michael Flynn.

In a triumph for President Donald Trump's three-year effort to overcome the taint of the Russia election meddling investigation, the court endorsed Attorney General Bill Barr's extraordinary decision to withdraw Flynn's prosecution on Wednesday, even though Flynn had already twice pleaded guilty to lying to FBI investigators about his Russian contacts.

The White House and Justice Department declared victory even as Democrats added the Flynn case to a list of examples they alleged showed Barr corrupting the judicial process to aid Trump politically.

White House spokeswoman Kayleigh McEnany called the decision, which can still be appealed, a "victory for justice and truth", while Trump said his former campaign advisor had been "persecuted".

"I'm very happy about General Flynn. He was treated horribly," Trump told reporters.

READ MORE: Transcripts released of Flynn's calls with Russian diplomat

Barr under attack

But House Judiciary Committee Chair Jerry Nadler said in a hearing that it was just another in a skein of cases in which Barr interfered to help Trump and his associates.

He cited Barr's recent intervention against his own department's prosecutors to secure a low prison sentence for another Trump advisor, Roger Stone; Barr's removal on Saturday of the department's top prosecutor in New York who was investigating Trump associates; and other alleged efforts by the attorney general to protect the president.

"He is the president's fixer. He has shown us that there is one set of rules for the president's friends, and another set of rules for the rest of us," Nadler said.

The appeals court decision in the Flynn case overruled a lower court judge who was poised to sentence the former Pentagon intelligence chief to prison.

Flynn agreed in December 2017 to plead guilty over his secret contacts with Russia's Washington envoy in a deal that formed the cornerstone to special counsel Robert Mueller's sprawling probe into whether Trump's election campaign colluded with Moscow.

But on May 7 Barr intervened and asked the court to drop the case completely, saying there was never any legitimate basis for the counterintelligence investigation against Flynn, which began under Trump's predecessor president Barack Obama.

Barr's intervention in the case pleased Trump, who had already hinted he could pardon Flynn.

But it opened a deep rift in the Justice Department, with the resignation of the federal attorneys who had prosecuted the case; and sparked outrage within the broader justice community.

Photo op 

Barr has increasingly become a lightning rod for opponents of Trump with a series of highly controversial moves.

He played a key role in opening up a rift between the White House and Pentagon over politicising the military when, with the secretary of defence and top US general present, he ordered troops to clear peaceful protestors from in front of the White House on June 1 so Trump could take pictures with top officials.

On Saturday he fired Geoffrey Berman, the US attorney in Manhattan, giving no particular reason.

But Berman had presided over the prosecution of Trump's lawyer Michael Cohen, a case in which Trump was depicted as an unindicted co-conspirator; and was investigating Trump's inauguration committee over financial irregularities, and probing another Trump lawyer, former New York mayor Rudy Giuliani.

Wednesday's hearing focused on other controversial steps by Barr.

Justice Department lawyer Aaron Zelinsky told the Judiciary Committee that Barr's decision to reduce the recommended sentence for Republican political consultant Roger Stone was done to satisfy Trump.

"Roger Stone was being treated differently from any other defendant because of his relationship to the president," he said.

A second Justice attorney, John Elias, said that Barr had personally intervened in the antitrust division to have legal cannabis companies investigated "because he did not like the nature of their underlying business."

In addition, he alleged, the antitrust division was ordered to investigate automakers over a legitimate emissions deal with California because Trump did not like it.

READ MORE: Trump alters his story on why he fired Flynn

Source: AFP