Stanley Fish has an interesting column about teaching law with specific reference to learning about constitutional law and the religion clauses. He says much that I agree with and that picks up on at least some of the themes in his entertaining, Save the World on Your Own Time.
A small but, I think, important feature of the column is the emphasis on (his variety of) intentionalism or purposivism to understand legal doctrine. He writes: 
One can, however, make the case that the practice of law is more than a technical/strategic exercise in which doctrines, precedents, rules and tests are marshaled in the service of a client’s cause. The marshaling takes place within an enterprise that is purposive. That is, law is more than an aggregation of discrete tactics and procedures; it is an enterprise informed by a vision of how the state can and cannot employ the legalized violence of which it is the sole proprietor. That vision will come into view in the wake of a set of inquiries. What obligations do citizens owe one another? How far can the state go in enforcing those obligations? What restrictions on what the state can do to (and for) its citizens should be in place? How do legal cultures differ with respect to these issues?
One can recognize ideas here that appear in some of Fish’s legal academic work. I am thinking primarily of There Is No Textualist Position in the San Diego Law Review some time back, as well as a piece criticizing Aharon Barak’s version of purposivism. Those pieces themselves derive in some measure from Fish’s anti-textualist views in literary theory, which I remember with some nostalgia from my years at Duke in the early 1990s. For Fish, intentionalism is not an interpretive method; it is interpretation itself. Textualism is ultimately empty.
The merits of intentionalism and textualism are a bit too heavy a topic so early in the morning, so instead it might be a little lighter to think about how an orientation toward one or the other in the classroom might influence one’s teaching. It seems to me that if one begins with the view that textualism is void and that intentionalism is all that there is to, say, interpreting religion clause cases, that one will naturally gravitate right away and as a primary issue to the sorts of questions that Fish wants to ask — questions about political and ethical obligations. These are important questions, to be sure, and they should be asked of students. But for the intentionalist of Fish’s stripe (the hard intentionalist), they are the bedrock — the first and ultimate standards by which we should think about law. That orientation will naturally color and structure one’s teaching in certain distinctive ways.
By contrast, the teacher who does not believe that textualism is empty or who thinks that there is more to interpretation than digging into first-order philosophical and political questions may take a different approach to teaching. That approach need not be technical or strategic or otherwise shallow. It might instead emphasize close reading, extraction of particular holdings and dicta, and — most of all — synthetic analysis and analogical argumentation from the specifics of the narrow text of cases and statutes.
None of this is to say that the sorts of questions that Fish asks, and wants to ask, law students, do not matter. I believe that they do, and that that they should play an important role in legal education. But I also think that law is not composed solely of, on the one hand, the asking and answering of these difficult questions, and, on the other, the possession of information relating to filing deadlines or the hours of operation of the clerk’s office. But I guess the larger thought is that one’s view of the merits of intentionalism and textualism may impact — perhaps in subtle ways — the type of learning experience that one will offer in the classroom.