WASHINGTON (AP) Donald Trump was acting within his role as president when he pressed claims about alleged fraud and irregularity in the 2020 election, his lawyers told a federal appeals court in arguing that he is immune from prosecution.

The attorneys also asserted in a filing late Saturday night that the historical fallout is tremendous from the four-count indictment charging Trump with plotting to overturn the election he lost to Democrat Joe Biden .

No other former president has ever been indicted; Trump has been indicted four times , in both state and federal court, as he campaigns to reclaim the White House.

The indictment of President Trump threatens to launch cycles of recrimination and politically motivated prosecution that will plague our Nation for many decades to come and stands likely to shatter the very bedrock of our Republic the confidence of American citizens in an independent judicial system, the attorneys wrote in a brief filed with the U.S. Court of Appeals for the District of Columbia Circuit.

At issue before the court, which has set arguments for Jan. 9, is whether Trump is immune from prosecution for what defense lawyers say are official acts that fell within the outer perimeter of a presidents duties and responsibilities.

U.S. District Judge Tanya Chutkan earlier this month rejected that argument, siding with prosecutors from special counsel Jack Smiths team and declaring that the office of the presidency does not confer a lifelong get-out-of-jail-free pass.

The appeals courts role in the dispute is center stage after the Supreme Court on Friday rejected a request from Smith to fast-track a decision on the immunity question. After Trump appealed Chutkans order, Smith urged swift intervention from the high court in an effort to get a speedy decision that could keep the case on track for a trial scheduled to start on March 4.

But with that request denied, the two sides are advancing their arguments before the appeals court, where a three-judge panel will decide as early as next month whether to affirm or overrule Chutkans decision.

In their latest filing, Trumps lawyers say that all of the acts Trump is accused of including urging the Justice Department to investigate claims of voter fraud and telling state election officials that he believed the contests had been tainted by irregularities are quintessential presidential acts that protect him from prosecution.

They all reflect President Trumps efforts and duties, squarely as Chief Executive of the United States, to advocate for and defend the integrity of the federal election, in accord with his view that it was tainted by fraud and irregularity, they said.

They also contend that, under the Constitution, he cannot be criminally prosecuted for conduct for which he was already impeached, but then acquitted, by Congress.

Federal prosecutors, by contrast, say Trump broke the law after the election by scheming to disrupt the Jan. 6, 2021, counting of electoral votes, including by pressing then-Vice President Mike Pence to not certify the results and by participating in a plot to organize slates of fake electors in battleground states won by Biden who would falsely attest that Trump had actually won those states.

Though Trumps lawyers have suggested that he had a good faith basis to be concerned that fraud had affected the election, courts around the country and Trumps own attorney general and other government officials have found no evidence that that was the case.