We all know that seniority among the Associate Justices is being determined by the time one joined the court. However, how is seniority determined when more than one Justice takes office at the same day?
Most recently we've had Lewis F. Powell, Jr. and William Rehnquist, confirmed and sworn-in at the same day in 1972. Rehnquist became the junior Associate Justice. Was that because Powell was older, or there were other factors in play?
While Powell and Rehnquist were nominated at the same time and they first sat on the court at the same time they were not confirmed on the same day. Powell was confirmed by the Senate three days before Rhenquist was, and judging by other cases where multiple justices were nominated jointly, it does appear that the order of Senate confirmation is the determining characteristic.
