A federal judge who was appointed by President Trump has ruled that the appointment of Robert Mueller as special counsel did not violate the Appointments Clause of the U.S. Constitution. This means that Mueller’s appointment is legal and has been validated by a federal court.

According to The Hill:

U.S. District Court Judge Dabney Friedrich, who was appointed by President Trump, on Monday denied a motion by Concord Management and Consulting LLC to dismiss an indictment on the grounds that Mueller was appointed unlawfully by Deputy Attorney General Rod Rosenstein, who is overseeing the Russia investigation.

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“The Special Counsel is an inferior officer because he is directed and supervised by the Acting Attorney General,” Friedrich wrote, referring to Rosenstein, who took over the Russia investigation after Attorney General Jeff Sessions recused himself.

“Although the Special Counsel regulations may not permit the Acting Attorney General to counterdemand certain decisions made by the Special Counsel, the Special Counsel remains subject to the Acting Attorney General’s plenary supervision,” the judge wrote.

“Second, Congress vested the Acting Attorney General with the power to appoint the Special Counsel,: Friedrich continued, citing past legal precedents that “make clear” Rosenstein, acting as attorney general with respect to the investigation, has the “necessary statutory authority” to appoint Mueller.

The judge reasoned that Rosenstein can appoint Mueller as an inferior officer, and holds supervisory power over the special counsel. This is a major validation and development in the Mueller investigation. Granting legitimacy to the special counsel will allow him to operate the investigation moving forward with that outstanding legal question answered.