And, I think it's even proper for the follow-up questions to penetrate with greater specificity, such as asking whether the Court has overstepped its bounds in particular areas, like abortion, the Commerce Clause and the incorporation doctrine (making federal constitutional rights applicable to the states through the 14th Amendment's Due Process Clause).
I realize that we're treading on delicate ground here. These issues, if not presently before the Court, inevitably will be in one form or another in the near future, and we don't want judges or judges in waiting to prejudge specific cases. But I would err on the side of trying to discover a nominee's judicial philosophy, being careful not to have him opine on specific cases.
After all, revealing a nominee's philosophy regarding these issues does not necessarily answer, conclusively, how he would rule in the context of a specific case before him, considering the many variables that might be involved.
I think we must try to find out in advance whether Supreme Court nominees believe they will sit as part of a superlegislature or as a passive, albeit usually final, arbiter.
I personally believe Judge Roberts is a political and ideological conservative. (His stated opinion that the Rehnquist Court has not been completely conservative would not likely have been uttered by a political liberal.)
I'm also convinced he is a rigorously strict constructionist, believing the Court should interpret law according to its textual and otherwise reasonably ascertainable meaning. I'm not sure to what extent he is an originalist, since he seemed to indicate his judicial philosophy cannot be neatly categorized, but I would bet that he'll try to defer to the Framers' original intent when possible.
I further suspect Roberts has a healthy reverence for the doctrine of stare decisis and that even the Supreme Court must give great weight to its own "established" precedent.
It seems to me that stare decisis and strict constructionism may well be on a collision course in many of the controversial constitutional areas likely soon to be revisited by the Court: abortion, same-sex marriage, Commerce Clause, Due Process incorporation issues, and the Tenth Amendment, to name a few.
I'm all for finding out what Roberts thinks about these competing forces in constitutional law and where he might come down on them -- apart from the context of actual cases. Conservatives, who occupy the high ground on the issue of the proper constitutional role of judges, should want to have this fight out in the open.
But alas I seriously doubt we'll find much out about these things until Judge Roberts is confirmed, which I believe he will be, and begins voting and delivering his written opinions.