With so much going on in the Russia investigation recently — the trial of Paul Manafort starting up, repeated denials of collusion from the White House — one major story seemed to get lost in the mix: A ruling from a federal judge may have actually moved Special Counsel Robert Mueller several steps closer to taking down Donald Trump.

The ruling, handed down by Judge Beryl Howell, was in a case filed by Andrew Miller, a close friend of Roger Stone. Stone, you may recall, allegedly played a major role in coordinating contacts between Russian hackers and WikiLeaks that led to the leaking of emails stolen from the Democratic National Committee (DNC) and members of Hillary Clinton’s 2016 campaign staff.

Miller had argued that Mueller couldn’t compel him to testify before a grand jury because the special counsel doesn’t have the authority under the Constitution. As CNN reports:

“[Attorneys for Miller argued] that Mueller was not nominated by the President and confirmed by the Senate and therefore was unconstitutionally appointed as a ‘principal officer.’ Howell found the claim unpersuasive in light of the Supreme Court’s decision in Morrison v. Olson, which upheld the constitutionality of provisions of a now-defunct federal statute creating an independent counsel, and subsequent court decisions.”

In her 92-page opinion, Judge Howell could not have been clearer, writing:

“[Mueller’s]  appointment, without presidential appointment and senatorial confirmation, thus did not violate the Appointments Clause.

“Multiple statutes authorize the Special Counsel’s appointment, and the official who appointed the Special Counsel had power to do so.”

And with that ruling, Judge Howell removed a major defense strategy for Trump’s attorneys, who had been expected to question the Constitutional authority of Mueller since he wasn’t appointed by the president or confirmed by the Senate. This line of defense had been one of the key strategies for Trump’s legal team if Mueller issues a subpoena to compel the president to testify before a grand jury.

In essence, Judge Howell handed the Mueller team a cudgel they can use against Trump as the case moves forward, and that could spell doom for the president in the very near future.