A federal judge ruled Monday that former White House counsel Donald McGahn must testify before the House of Representatives impeachment probe. Judge Ketanji Brown Jackson of the US District Court for the District of Columbia concluded that “Presidents are not kings” and “individuals who have been subpoenaed for testimony by an authorized committee of Congress must appear for testimony in response to that subpoena.”

McGahn was subpoenaed by the House in April to testify on matters relating to the Mueller Report. The Department of Justice (DOJ) released a memo in May arguing that senior presidential advisors cannot be called on to testify about their duties. The House Judiciary Committee filed this lawsuit in August after negotiations with McGahn failed.

Jackson first asserted that the federal court has jurisdiction over the issue, stating that the judiciary’s involvement in solving this conflict “advances … rather than subverts” the principles of separation of powers.

The DOJ argued that the Executive Branch has an interest in autonomy and can prevent the inquiry powers given to Congress in Article I of the US Constitution. Jackson responded by saying, “it is a core tenet of this Nation’s founding that the powers of a monarch must be split between the branches of the government to prevent tyranny.”

Jackson pointed out that ordinary civil litigants have access to the courts to seek subpoenas and questioned why a Committee of Congress should be treated less favorably when acting to pursue its Constitutional interests. Additionally, she noted that presidential autonomy cannot mean that the Executive is totally insulated from Congress—that would destroy the historical oversight function of Congress.

The opinion notes that Office of Legal Counsel opinions stating that Presidential Advisors have this immunity are no more than persuasive authority, stating that “the Executive cannot be the judge of its own privilege.”

Jackson concluded that when “Congress issues a valid subpoena to a current or former Executive branch official … the subpoenaed official does, as a matter of law, have a duty to respond notwithstanding any contrary order of the President”

McGahn’s attorney has stated that he will comply with the order unless the DOJ appeals it.

House Intelligence Committee Chairman Adam Schiff stated, “The witnesses who have defied Congress at the behest of the President will have to decide whether their duty is to the country, or to a President who believes that he is above the law.”