O'Connor's Resignation and Rehnquist's Death:

Some time back, we had a debate here (I think Jim raised it) that touched upon the legal effect of O'Connor's resignation letter. Here's my question--in light of the fact that there are two vacancies, could O'Connor simply announce today that she is withdrawing her earlier letter announcing that she was retiring effective upon the "nomination and confirmation of my successor" and simply state, "My resignation is now effective upon the nomination and confimation of Justice Rehnquist's successor"?

The term "Chief Justice" is not mentioned in Article III. I am not a Supreme Court jock so I'm not sure where that honorific arises (presumably in legislation somewhere or Court rules), but why couldn't they simply designate Stevens as acting chief, and allow O'Connor to stay on the Court effective on the confirmation of Rehnquist's successor, thereby keeping the Court at is full 9 member strength pending a replacement for Rehnquist?

What is the legal relevance of O'Connor's resignation letter, and could she simply withdraw or amend it prior to the appointment of "her" successor? Is Roberts truly "her" successor, or is the legally-relevant fact whether there is a vacancy on the court, as opposed to the notion of vacancies in particular seats? Isn't the legally-relevant act here the appointment of the successor, not the resignation letter itself?

More generally, it seems to me that there is a peculiar ambiguity in the law when legal obligations are to be triggered (or are thought to be triggered) by private actions, such as the submission of a resignation letter by a member of the Court. A few years ago I published an article on the Presidential Transition Act which asked the question about when an individual was to be named the "President-elect" for purposes of the Presidential Transition Act. The executive branch official in charge of making the determination suggested that one factor to determine would be whether the opposing candidate made a concession. If you will recall, in the 2000 election, Gore almost conceded late on election night, but then changed his mind. Would it have made a legal difference if he had actually conceded? If he did concede then later changed his mind, would that have undone the "President-elect" designation for Bush? I argue that it would not have, as there is no good argument for having the authority of naming the President-elect, a legal term, be determined by a private party (there one of the candidates).

Update:

SCOTUS Blog has more.