From the Supreme Court's opinion today in Collins v. Yellen:
... But the nature and breadth of an agency’s authority is not dispositive in determining whether Congress may limit the President’s power to remove its head. The President’s removal power serves vital purposes even when the officer subject to removal is not the head of one of the largest and most powerful agencies. The removal power helps the President maintain a degree of control over the subordinates he needs to carry out his duties as the head of the Executive Branch, and it works to ensure that these subordinates serve the people effectively and in accordance with the policies that the people presumably elected the President to promote. ...
Courts are not well-suited to weigh the relative im-portance of the regulatory and enforcement authority of dis-parate agencies, and we do not think that the constitution-ality of removal restrictions hinges on such an inquiry.
And from a footnote:
Amicus points to the Social Security Administration, the Office of Special Counsel, the Comptroller, “multi-member agencies for which the chair is nominated by the President and confirmed by the Senate to a fixed term,” and the Civil Service. ... None of these agencies is before us, and we do not comment on the constitutionality of any removal restriction that applies to their officers.
And from the concurrence of Justice Kagan:
... Without even mentioning Seila Law’s “significant executive power” framing, the majority announces that, actually, “the constitutionality of removal restrictions” does not “hinge[]” on “the nature and breadth of an agency’s authority.” ... Any “agency led by a single Director,” no matter how much executive power it wields, now becomes subject to the requirement of at-will removal. ... And the majority’s broadening is gratuitous—unnecessary to resolve the dispute here....
And from the concurrence of Justices Sotomayor and Breyer:
Never before, however, has the Court forbidden simple for-cause tenure protection for an Executive Branch officer who neither exercises significant executive power nor regulates the affairs of private parties.
I thought it was already clear that the President's inability to remove the Commissioner at will was unconstitutional. I think it's now quite clear where the Supreme Court is headed or, should I say, has gone. I see no reason why the President should tolerate Saul any longer. Any attempt he makes to stay in office isn't going to work.