Constitutionalism and the Is-Ought distinction

Orin Kerr and Sasha Volokh have an interesting back-and-forth here about the is/ought distinction in constitutional law. Kerr claims that 'many people who discuss constitutional law are pretty sloppy in distinguishing "is" and "ought." When asked what the Constitution means, lots of people construct a pastiche of existing law and law that they personally would really like.' On his view, talking about constitutional law descriptively means "trying to describe what the law is in the same way [one] might describe the law to a client who needs to know the legal consequences of particular conduct."

Volokh points out that there are other ways of interpreting the constitutional "is" than this "bad man" view of law; we might believe that unenforced constitutional rules are still law despite a lack of institutional sanction, for example. Kerr thinks this is entirely consistent with his point: "My position was that by law I meant the doctrine of legal institutions -- courts, legislature, and executive, in whatever mixture." Or as he put it in his reply, law is "what legal institutions believe it they must do or not do using widely shared practices of interpretation."

But once Kerr has acknowledged this, his original claim--that many people are "sloppy" about is and ought, joining together what they want the law to be with what it actually is--starts looking a lot more questionable. Is Kerr's claim that normative arguments have no role to play in determining exactly how the actions of governmental branches create legal content? That they have no role to play in determining the limits of the relevant interpretive community?

One needn't be a Dworkinian to think that normative arguments are relevant to the content of constitutional norms; all but the hardest of hard positivists think so. And once you allow for this, then it is entirely reasonable for someone to challenge your description of a constitution's content on the grounds that it fails to properly reflect normative considerations.