Democrats have been fighting in court for months to enforce a subpoena for McGahn to testify as part of the impeachment proceedings in Congress. They argue that McGahn's testimony is "central" to parts of the House committee's investigation into Trump, which is not yet complete even though the Democratic-led chamber passed two articles of impeachment against him last week .

Lawyers for the House Judiciary Committee said Monday that the panel could draft and recommend "new articles of impeachment" against President Donald Trump if additional evidence is revealed by former White House counsel Don McGahn.

And McGahn's testimony is "also relevant to the Committee's ongoing investigations into Presidential misconduct and consideration of whether to recommend additional articles of impeachment," lawyers for the Judiciary Committee wrote in a submission to the Washington, D.C., Court of Appeals.

Click here or scroll down to read the House Judiciary Committee's court filing

"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 wrote.

Trump was impeached on two articles — abuse of power and obstruction of Congress — related to his efforts to have Ukraine President Volodymyr Zelenskiy announce investigations involving former Vice President Joe Biden and his son, and a debunked conspiracy that Ukraine, not Russia, interfered in the 2016 presidential election.

Trump allegedly withheld hundreds of millions of dollars in congressionally approved military aid to Ukraine while he was pushing for the probes into his political rivals. His administration refused to comply with congressional Democrats' impeachment inquiry and has pressured numerous government witnesses not to cooperate.

The Judiciary Committee's court filing Monday followed an entry from attorneys for the Justice Department, who argued that the House's vote to impeach Trump undermines the push from Democrats to have McGahn's subpoena enforced quickly.

The DOJ lawyers wrote that there is no longer "any justification for otherwise expediting the Court's decision in this case," outside of an already scheduled Jan. 3 hearing, where both sides will argue their cases.

But the Judiciary Committee's attorneys countered that Trump's impeachment in the House has "reinforced," rather than undercut, the need for an "expeditious resolution of this appeal."