please see my post #948 that quotes the President's public statement when he switched the Roberts nomination to apply to Rehnquist rather than O'Connor.
I think you are right that vacancies by death take precedence over vacancies by resignation, especially when the resigning O'Connor offered to stay on the court until her replacement was confirmed.
What few people know is that if the SCt Term had opened with the center chair vacant, John Paul Stevens as the senior member of the court in years served would have been acting Chief for administrative purposes: assigning who will write opinions, for example. Obviously conservatives did not want Stevens filling that role for any length of time, so the Rehnquist seat needed to be filled quickly.
But now that Roberts is Chief he is the "senior member" of the Court--the Chief is considered the senior member of the Court regardless of how many years he has actually been on the Court.
I used to work for a lawyer who argued a few SCt cases so I know all kinds of stuff like this.
I think Scalia was probably very disappointed, but he is a lightning rod figure now and could not have been confirmed as quickly as Roberts. Bush really needed to get a Chief before the First Monday in October because of the Stevens situation I explain above.
Totally correct. Bush was in a "Git r' done" pinch, and making Roberts the Chief Justice was the easiest way to do that. Scalia would have made an AWESOME Chief Justice, but it was would have made things VERY complicated.