In large measure I agree with both Mark and Gerry: there are a good many questions that may be asked about judicial philosophy that, to my mind at least, are substantially more illuminating than simply asking a candidate his legal opinion concerning hypothetical cases (e.g., gay marriage and abortion) likely to come before the Court. Thus, he can be asked about how he believes the Constitution should be interpreted: is it a living document? Are you limited to the text? Should you consider original intent? Should you look to legislative history? How should (or should) public policy be considered in the deliberative process? How do you view stare decisis in the constitutional context? What is the role of the Supreme Court? For example, if a law is “unjust” but comports with the text of the Constitution, should the judge strike it down under an evolving standard? Do the other branches have a role in interpreting the Constitution? What deference should the other branches/states be given. Etc.
This will quite frankly tell everyone what they need to know. The obstructionists won’t be happy with anyone who doesn’t view the Constitution as a living wish-list of liberal policy, and the court as a super-legislature promoting the same; while the conservatives will have a good idea how he will approach “novel” legal innovations. If you really need more, questions could be asked about specific areas of the Constitution, so long as the questions themselves were sufficiently general. For example, if he were an originalist, one might ask what this methodology would mean for interpretation of the First Amendment, which has strayed so far from its original moorings. This may quickly become a “how far is too far” game, but, as Gerard points out, a nominee may be able to step the questions back to a greater level of abstraction, or if the questions go too far, beg that he can’t answer due to the canons of conduct.
The obstructionists entire game, however, will be to ask him questions and the administration for documents that they know are inappropriate. My sense is that when Schumer and Kennedy ask questions, there will be no fine determinations needed: the questions will be well on the other side of what a nominee should answer about his views on cases which are all-but-certain to come before the court.
So ask away about judicial philosophy and methodology—you’ll learn everything you need to know about how he will approach the law. But express questions about legal positions on issues like gay marriage or abortion which are likely to come before the court should not be answered based on the canons, appearance of impartiality, and prudence.