Lawyers for the House Judiciary Committee floated the possibility that the panel could take up additional articles of impeachment against President Donald Trump, according to a document filed in a federal appeals court Monday.

Urging the court to compel former White House counsel Don McGahn to testify, the committee's lawyers said that his testimony could lead to more revelations about the president's behavior.

“If McGahn’s testimony produces new evidence supporting the conclusion that President Trump committed impeachable offenses that are not covered by the articles approved by the House, the committee will proceed accordingly — including, if necessary, by considering whether to recommend new articles of impeachment,” the lawyers said.

In a separate filing Monday, the Department of Justice argued the appeals court should reject the House's bid to force McGahn to testify. "This court should decline the committee's request that it enter the fray and instead should dismiss this fraught suit between the political branches," the DOJ filing says.

The House sued to force McGahn to testify in August after the White House directed him not to testify before the Judiciary Committee. The White House and the Justice Department argued McGahn had "absolute immunity" from testifying before Congress.

McGahn is a key figure in former special counsel Robert Mueller's investigation into the Trump campaign and Russian interference in the 2016 presidential election. He met with Mueller's investigators for over 30 hours, and his name is mentioned over 500 times in the report.

He's also a key player in what Democrats believe is one of the clearest cases of obstruction of justice outlined in Mueller's report: Trump’s directive that McGahn fire Mueller. Trump has publicly disputed the former White House lawyer’s account, placing greater importance on what McGahn would testify to publicly under oath before Congress.

A Washington federal court judge ruled in the House's favor in November, finding "absolute immunity from compelled congressional process simply does not exist."

"Presidents are not kings," the judge, Ketanji Brown Jackson, said in her ruling.

The case is scheduled for argument before the appeals court Jan. 3.

The House impeached Trump for abuse of power and obstruction of Congress last week.