Donald Trump's former aide Steve Bannon faces possible prison time Friday, when a judge will set his sentence for refusing to testify in Congress' probe of the January 6, 2021 attack on the Capitol.

Bannon, a longtime political strategist and vocal advocate for the Republican former president, was found guilty in July on two counts of contempt of Congress for defying a subpoena to testify.

The Justice Department urged the court Monday to sentence the 68-year-old to six months in prison -- the high end of sentencing guidelines but less than the maximum possible 12 months -- and fine him $200,000, pointing out that Bannon had repeatedly sought to delay the proceedings by hinting he might cooperate.

Bannon "has pursued a bad-faith strategy of defiance and contempt," the department said.

Bannon, who currently runs a streaming political commentary website, asked the court to sentence him to probation, saying he had rejected the congressional subpoena on the advice of his lawyers.

He also asked that the court place a stay on the implementation of any sentence while his appeal of the original verdict goes ahead.

"Mr. Bannon respectfully asserts that a sentence of incarceration would violate his constitutional rights," his submission said.

The investigation by a special House committee has depicted Bannon as knowing in advance of the plan by hardline Trump supporters to attack the Capitol on January 6 to prevent Democrat Joe Biden from being confirmed as the next president.

It also showed him advocating for Congress to block Biden -- who defeated Trump in the November 2020 election -- from becoming president.

"The rioters who overran the Capitol on January 6 did not just attack a building -- they assaulted the rule of law upon which this country was built and through which it endures," the Justice Department told the court in its sentencing memo.

"By flouting the Select Committee's subpoena and its authority, the defendant exacerbated that assault."

Bannon was one of the masterminds behind Trump's original presidential campaign and victory in 2016.

He served in the White House for the first seven months of Trump's term as chief strategist, leaving reportedly due to conflicts with other top staffers.

In 2020, Bannon was charged together with others with wire fraud and money laundering for taking millions of dollars for personal use that donors contributed to their scheme to build a wall on the border with Mexico.

While others were found guilty in the scheme, before leaving office in January 2021, Trump issued of blanket pardon for Bannon, leading to the dismissal of the charges against him.