House Democrats have withdrawn a subpoena for testimony from Charles Kupperman, a former top national security aide to President Trump, House lawyers told a federal judge in Washington on Wednesday.

House lawyers, seeking to avoid delay in the impeachment hearings, asked U.S. District Judge Richard Leon to dismiss a lawsuit Kupperman filed to try to resolve conflicting orders from Congress and the White House over his participation in the investigation into the president.

The House told Leon in a court filing that with the subpoena withdrawn, Kupperman’s lawsuit was moot and should be dropped.

Instead, the House said that in the interest of speed, it would look to the outcome of another case that is further along in judicial proceedings — that involving a subpoena to former White House counsel Donald McGahn. That case raises similar issues of whether the White House can bar high-ranking administration officials from testifying.

In the McGahn case, a different judge at the same courthouse in Washington heard oral arguments last week and has said she probably would issue an opinion before the end of November.

Leon had set oral arguments in the Kupperman lawsuit for Dec. 10.

Attorneys for Kupperman and Trump had yet to take a position on the House request, according to the House filing, and Kupperman’s lawyer declined to comment Wednesday evening.

Leon held a short conference call Wednesday evening and declined to dismiss the case, saying any decision to withdraw the lawsuit was solely up to Kupperman and his lawyers, according to a transcript of the call.

Leon said the briefing schedule would stand, the transcript shows. “It is critical, in my judgment, that this matter stay on track,” he said. “Considering that the House and the Department of Justice have already researched and briefed these issues, the Court sees no reason why we cannot continue on the course that’s been set.”

Kupperman served as deputy to John Bolton when Bolton was national security adviser and is an important witness for Democrats on Capitol Hill. His lawsuit had potential implications for Bolton, who is represented by the same attorney as Kupperman. Bolton and Kupperman are longtime Republican advisers and had access to private deliberations at the White House involving the president’s communications about Ukraine.

Justice Department lawyers have argued that the president’s top aides have “absolute immunity” from congressional subpoenas and that the House “as a general proposition” can never sue the executive branch or compel top White House aides to appear.

Regarding Kupperman’s case, House lawyers on Wednesday said in filings that “in light of the status of the House’s impeachment inquiry, House Defendants have no current intention to reissue the subpoena to Plaintiff.”

The plan by House Democrats to rely on the outcome of McGahn’s case was disclosed in a letter from the chairmen of three House committees to Kupperman’s lawyer and was submitted as an attachment in Wednesday’s court filing.

The chairmen laid out what they thought Kupperman’s lawyer should do: “Unless your lawsuit was admittedly only for purposes of delay, and without a subpoena in force, the Committees expect that your client will voluntarily dismiss the complaint he filed in the United States District Court for the District of Columbia on the same day he received the Committee’s subpoena and be guided by the decision in McGahn,” the committee chairmen wrote in their letter to Charles Cooper, who represents Kupperman.

At a hearing in McGahn’s case last week, U.S. District Judge Kentanji Brown Jackson expressed skepticism about the Trump administration’s claim that Congress cannot compel the former White House counsel and top presidential aides to testify. She called it a “peculiar” argument that threatens to upset the Constitution’s system of checks and balances.

Tom Hamburger and Ellen Nakashima contributed to this report