Even though House Democrats withdrew their impeachment subpoena of a former National Security Council official, a lawsuit over whether the subpoena is enforceable will continue, a federal judge told the parties Wednesday evening.

U.S. District Judge Richard Leon said that only the official, Charles Kupperman, can voluntarily dismiss the case, according to transcript from a closed door teleconference with lawyers in the case. The House had asked Leon to dismiss the case in a court filing earlier Wednesday.

“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,” Leon said.

The case concerns whether the President’s top advisors are covered by “absolute immunity” that makes the House’s subpoena for his testimony unenforceable. The question is similar to the claim the White House is making in opposing a House subpoena of former White House counsel Don McGahn in a separate matter.

Kupperman proactively brought this lawsuit against the House, the President, Speaker Nancy Pelosi and three committee chairs after being subpoenaed for Ukraine-related testimony in the impeachment inquiry. His lawyers say he has “no dog in the fight” over whether to comply with subpoena or with the White House’s directive he not testify. Kupperman is seeking clarity from the court as to whether the White House’s “absolute immunity” claim trumps the House subpoena.

Wednesday’s teleconference was scheduled hours after the House flagged for Leon that the committees seeking Kupperman’s testimony had withdrawn their subpoena.

“The withdrawal of the subpoena at issue here has eliminated any present, impending, or foreseeable injury to Plaintiff. At minimum, there is no good cause for expedition,” the House said in its filing, while suggesting the briefing schedule be slowed to a standard pace if the case was not going to dismissed outright.

The House also wrote a letter directly to Kupperman’s lawyers telling them that they expect Kupperman to follow whatever ruling comes out of the McGahn case, in which a judge heard oral arguments last week. The House noted that other administration officials have testified in the Ukraine inquiry.

Leon said Wednesday evening that he was “fully appreciative that the decision to voluntarily dismiss this lawsuit is solely up to Mr. Kupperman and his counsel.”

He said the House could argue that the case was now moot when it filed a motion to dismiss, which had already been scheduled in the briefing schedule.

“There is no need for further briefing schedule conference on this point, as far as I’m concerned,” Leon said. “It is critical, in my judgement, that this matter stay on track.”