CJUS

Since there seems to be some confusion in the comments here I’m guessing there may be a more general misunderstanding of this point. The Chief Justice is a separate appointment, and there’s no requirement (formal or informal) that a justice will be promoted from within. Historically, Rehnquist was an exception: of the 16 Chief Justices, only 3 were appointed after being associates–Rehnquist, Stone, and White. (In addition, LBJ tried to elevate Abe Fortas to replace Warren, but the nomination failed; I’m not sure if there are others.) There’s nothing constitutionally problematic about Bush nominating Roberts as Chief rather than associate. (Mark Tushnet has suggested on the lawcourts listserv that Roberts has less combined major political and judicial experience than anyone ever appointed as Chief, which seems right, although it’s up for the Senate to take that into account.)