The chief justice is automatically #1 in seniority. The associate justices are ranked according to the amount of time they've been on the Court.
Two important implications are:
- The senior justice on each of the majority and minority sides in a given case, assigns the task of writing the majority and minority opinions. That can be more than just a housekeeping matter. While, in a big-picture sense, an opinion-writer is bound to conform his or her writing to the position to which they've committed themselves, the details of the opinion can shape the case law in subtle ways. Also, assigning an opinion to a wavering justice is sometimes a tactic that a senior justice uses to keep the waverer onside.
- After the justices hear oral argument on a case, they meet in conference to discuss their opinions on the case. The justices speak in order of seniority. While everyone has a chance to be heard, those who speak earlier in the process have more power to shape the discussion than their more junior colleagues.
Those powers that are tied to seniority are the main ways in which the position of chief justice is more powerful than that of associate justice.
But, as I alluded to in the title of this post, there is another aspect of seniority, or, more accurately, the lack thereof, that is more trivial (although it perhaps doesn't seem that way if one is stuck in the junior position for a long period of time).
When the justices meet in their conference room to discuss cases, they are the only nine people in the room. No staff. No news media.
If staff need to get a message to the justices, they knock on the door of the conference room. The most junior of the associate justices is seated nearest the door, and is assigned the task of getting up and retrieving such messages.
After President Bill Clinton appointed Stephen Breyer to be associate justice, in 1994, there was an unusually long period of time before another associate justice position was vacated. Breyer remained the junior justice, until Sandra Day O'Connor's retirement became effective, in 2006. So, Breyer had the dubious distinction of having the longest tenure as Supreme Court doorman, in modern times.
If, as expected, Sonia Sotomayor is confirmed by the Senate, she will become doorwoman. Odds are she will not stay in that position as long as Breyer did. Even if all of the associate justices other than John Paul Stevens stay on the Court for another 12 years, Stevens would have his 100th birthday, before Sotomayor would have been on the Court for 12 years. Strom Thurmond served in the Senate until the age of 100, so could Stevens do the same on the Supreme Court? Is 100 the new 80?