McGahn asked President Barack Obama-appointee Judge Kentanji Brown Jackson, a district court judge in Washington, for a temporary stay on Wednesday morning.
Jackson granted the temporary stay while she decides whether to grant McGahn a longer stay which would block him from having to appear as he appeals her decision.
The House Judiciary Committee, which asked the court to enforce the subpoena, said it didn’t oppose the temporary stay.
McGahn is being represented by the Department of Justice, which said it was appealing Jackson’s decision.
Jackson in her ruling rejected the White House’s “absolute immunity” argument to prevent McGahn from appearing to testifying, saying that McGahn is required to appear before the House Judiciary Committee for testimony but is allowed to assert privilege on questions asked during a hearing, where appropriate.
“This Court holds that individuals who have been subpoenaed for testimony by an authorized committee of Congress must appear for testimony in response to that subpoena—i.e., they cannot ignore or defy congressional compulsory process, by order of the President or otherwise,” Jackson wrote in her opinion.
The White House confirmed that the administration will also appeal the ruling, adding that they were “confident that the important constitutional principle advanced by the administration will be vindicated.”
“This decision contradicts longstanding legal precedent established by administrations of both political parties,” White House press secretary Stephanie Grisham said in a statement.
McGahn, who was viewed as a key witness in former special counsel’s Robert Mueller’s investigation, was subpoenaed by the House Judiciary Committee in April to provide documents and appear before lawmakers as part of their investigation of possible obstruction of justice by Trump—something that Mueller did not conclude in his report. Trump has denied any wrongdoing.
The White House blocked his appearance in May, asserting privilege over the documents. This prompted House Democrats to subsequently sue McGahn in August in an attempt to enforce the subpoena.
Jackson’s initial ruling asserting McGahn had to comply with the subpoena doesn’t apply to former National Security Adviser John Bolton and Bolton’s ex-deputy, Charles Kupperman, a lawyer representing both said this week.
“In McGahn, the House Judiciary Committee emphasized to the district court that the information it sought from Mr. McGahn ‘did not involve the sensitive topics of national security or foreign affairs,” the attorney said in a statement.
“Therefore, any passing references in the McGahn decision (instead of court’s opinion) to Presidential communications concerning national security matters are not authoritative on the validity of testimonial immunity for close White House advisors, like Dr. Kupperman, whose responsibilities are focused exclusively on providing information and advice to the President on national security.”
Kupperman filed a lawsuit asking a court to rule whether he should comply with a subpoena or obey the White House’s order for him not to comply.
Janita Kan contributed to this report.