Setanta wrote:Traditionally, the Chief Justice is chosen from among sitting justices.
There is no such tradition. Of the sixteen chief justices (including one recess appointment) only three have been promoted directly from the ranks of the associate justices: Edward White, Harlan Fisk Stone, and Rehnquist. A fourth, Charles Evans Hughes, served as an associate justice but resigned from the bench and was then appointed as chief justice after a 14-year hiatus. None of Rehnquist's three immediate predecessors, Fred Vinson, Earl Warren, and Warren Burger, were associate justices at the times of their appointments.
Another odd bit of trivia: Rehnquist is the first member of the supreme court to die in office since Wiley Rutledge in 1949, and one of Rutledge's clerks, John Paul Stevens, is currently the senior justice on the supreme court and will take over Rehnquist's duties until the senate confirms a new chief justice.