Whenever the Chief Justice is unable to perform the duties of his office or the office is vacant, his powers and duties shall devolve upon the associate justice next in precedence who is able to act, until such disability is removed or another Chief Justice is appointed and duly qualified.
28 U.S. Code § 3 - Vacancy in office of Chief Justice; disability
The sentence, “This provision shall apply to every Associate Justice who succeeds to the office of Chief Justice”, was omitted as covered by last portion of revised section.
Minor changes were made in phraseology.
For seniority of commissions, see section 4 of this title.