House Democrats withdrew a subpoena Wednesday for a former national security official to testify in the impeachment inquiry into President Trump Donald John TrumpFederal prosecutor speaks out, says Barr 'has brought shame' on Justice Dept. Former Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick MORE.

Democrats pulled the subpoena for Charles Kupperman, who served as a deputy to former national security adviser John Bolton John BoltonJudge appears skeptical of Bolton's defense of publishing book without White House approval Maximum pressure is keeping US troops in Iraq and Syria Woodward book trails Bolton, Mary Trump in first-week sales MORE, about a week after a federal judge fast-tracked the case.

“The subpoena at issue in this matter has been withdrawn and there is no current intention to reissue it,” Democrats wrote in their request, according to a court filing. ADVERTISEMENT

Although Democrats said they won't reissue the subpoena, the chairmen of the committees leading the impeachment investigation asked Kupperman’s attorneys if the former Bolton aide would testify if the court rules in a separate case that former White House counsel Don McGahn must comply with his subpoena.

In both cases, the dispute centered around Trump’s argument that his aides have “absolute immunity” from complying with congressional subpoenas.

“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 of the District of Columbia on the same day he received Committee’s subpoena and be guided by the decision in McGahn,” House Intelligence Committee Chairman Adam Schiff Adam Bennett SchiffSchiff to subpoena top DHS official, alleges whistleblower deposition is being stonewalled Schiff claims DHS is blocking whistleblower's access to records before testimony GOP lawmakers distance themselves from Trump comments on transfer of power MORE (D-Calif.), Foreign Affairs Committee Chairman Eliot Engel Eliot Lance EngelHouse panel halts contempt proceedings against Pompeo after documents turned over Engel subpoenas US global media chief Michael Pack The Hill's Morning Report - Sponsored by The Air Line Pilots Association - Pence lauds Harris as 'experienced debater'; Trump, Biden diverge over debate prep MORE (D-N.Y.), and acting Oversight and Reform Committee Chairwoman Carolyn Maloney Carolyn Bosher MaloneyPelosi, Democrats unveil bills to rein in alleged White House abuses of power Government watchdog recommends creation of White House cyber director position Top Democrats call for DOJ watchdog to probe Barr over possible 2020 election influence MORE (D-N.Y.) wrote in a letter to Kupperman's attorneys.

Kupperman’s attorneys, Michael Kirk and Charles Cooper, did not immediately respond to requests for comment.

"There is no proper basis for a witness to sue the Congress in court to oppose a duly authorized congressional subpoena," a House Intelligence Committee official said Wednesday. "Nevertheless, given the schedule of our impeachment hearings, a court process that leads to the dismissal of Dr. Kupperman’s flawed lawsuit would only result in delay, so we have withdrawn his subpoena."

"If Dr. Kupperman or other witnesses over whom the White House might assert absolute immunity to prevent their testimony are truly interested in honoring their duty to uphold the Constitution instead of hiding behind the White House’s improper directions, they have every opportunity to do so, as numerous current and former officials — both senior and more junior — have courageously done," the official added.

An attorney for Kupperman had previously described the former aide as being caught in a “classic Catch-22,” between the request to testify and Trump’s argument that administration officials have immunity from complying with the subpoenas.

Kupperman is considered a key witness since he was on the July 25 call between Trump and Ukrainian President Volodymyr Zelensky that is at the center of the impeachment inquiry.

Judge Richard Leon, a George W. Bush appointee, had fast-tracked the case over the disputed subpoena, setting a Dec. 10 date for oral arguments.

But House Democrats are readying to moving the impeachment inquiry forward, setting the first public hearing dates for next week.

Democrats announced Wednesday that three witnesses will testify in public hearings next week.

William Taylor, the top U.S. diplomat to Ukraine, and George Kent, a top State Department official, will testify next Wednesday. Former U.S. Ambassador to Ukraine Marie Yovanovitch is expected to testify next Friday, according to Schiff.

So far, all testimony has been given behind closed doors. House Democrats began releasing transcripts of those depositions earlier this week.