(sent to conlawprof)
... I think we would need to know what "same methodology" referred to. It seems that the only ethical requirement for good casuistry is to avoid internal contradictions and being fickle (changing your mind all the time). I could think of one having a very complicated decision constituence that deployed modalities of thought with purpose. For example, one might be a pragmatist if consequences became super extreme (civil war and the like) but be more orthodox if they are not. The same exact judge might be a "natural law" theorist for certain things (like non-amendment clauses in constitutions) but be a positivist for the other things constitutions say. These are not contradictions; they are choices made with purpose that construct the judicial belief system. So I think the only requirement here is that the judge has to justify within the body of belief why the modality is switching and what, therefore, the belief constituence consists of.
At the end of the day, I bet all that one can get here is something in the nature of a character assessment. You say, in effect, "baloney" if you find the belief constituence is a poor offering. I say this myself when I see Scalia being originalist for historical text but textualist for contemporary text. (In fact, one could argue it is more rational to switch these).
At the end of the day, judging casuistry is no different than judging art. Really, that is all there is to philosophy of law at the (very) end of the day. The issue is whether the craft has "integrity" within the community who make up the cultural practice.
Dr. Sean Wilson, Esq.
Wright State University
Redesigned Website: http://seanwilson.org/
SSRN papers: http://ssrn.com/author=596860