There is a very good post by Fr. Christopher Smith at The Chant Café raised by, but not limited to, the norms issued by the Diocese of Phoenix for Communion under both kinds.
People all over the blogosphere were quick to turn to Church documents to support their positions for and against Olmstead’s now reversed decision. I was one of them, and even posted some of the pertinent documents in a post on Chant Café. As I watched the commentary on this issue develop, I came to realize something which frankly makes me quite uncomfortable. Everyone could appeal to authoritatively binding Church documents, without modifying or falsifying their meaning, for their position.
So this begs the question: what is the proper hierarchy of documents related to the liturgy? Theologians before the Second Vatican Council often used a system to rank the relative gravity of theological propositions: de fide divina, de fide ecclesiastica, and so on. That system has disappeared, and so there is a lack of clarity as what the weight of a papal encyclical is as opposed to, oh, for example, a note of the Vatican dicastery Iustitia et pax, or a comment made by the Pope in an interview on an airplane and an instruction of the Congregation for the Doctrine of the Faith.
Against the bewildering plethora of liturgical documents in different times and places, with no discernible ranking as to their weight and authority, we have several levels of actual practice, which are in turn sometimes enshrined in law. We have the practice of the Roman Pontiff, we have the norms of the Universal Church, the norms of the Episcopal Conferences, the norms of individual Ordinaries, the policies and praxis of individual pastors, then of individual celebrants, and then the idiosyncracies of all of them. In turn, again, we have the multiplication of endless options in the liturgical books themselves for everything under the sun, and then the reality that there are many priests and communities that just do whatever they want.