Ad Orientem

What arrangement of the Mass chants emerges before the eyes of an unbiased reader of the Liturgical Constitution promulgated by the Second Vatican Council? If we disregard what happened after the Synod, and concentrate our attention upon the text of Sacrosanctum Concilium, this is the picture we get:
The Mass is celebrated in most cases in Latin (Art. 36), although some parts (lections, bidding prayer: Art. 54) sometimes (when and where it seems useful) can be said in the vernacular (Art. 36/2). The faithful are able to chant the responses, the acclamations, and the Ordinary in Latin (Art. 54, cf. Kyriale Simplex). Gregorian chant has pride of place in liturgical singing (Art. 116). The chants of the Proper are sung by a choir or schola (Art. 114), in larger churches from the Graduale Romanum, and in smaller ones from the Graduale Simplex (Art. 117); but the congregation, too, may join in the Chant (Art. 114), singing psalms and antiphons (Art. 30). Chant is complemented by sacred polyphony taken from the heritage of sacred music, or from a repertory of new compositions. These take their texts chiefly from the Holy Scriptures or the liturgical books (Art. 121), correspond at all points with the spirit of the liturgy (Art. 116), and are characterized by the hallmarks of true ecclesiastical thinking (Art. 121) and true art (Art. 112). Careful instruction must prepare the laity to take their part in liturgical singing, and so each part is sung by the very person concerned (Art. 28, 114), and yet in the way required by the nature of the given part (Art. 112). Congregational religious hymns are also accepted during various devotions, as well as in liturgical celebrations “in keeping with rubrical norms and requirements.” However, in consequence of all these stipulations the meaning of ‘congregational hymnody’ has been changed: people sing not only vernacular hymns but also many parts that are integral components of the liturgy. Hence it seems right to distinguish the cantus populi (the chanting of the people) from cantus popularis (popular religious songs). The first of these is plainly the task of present and future; it is the great task of the liturgical renewal in the field of congregational chant.

(László Dobszay – The Bugnini Liturgy and the Reform of the Reform, p. 85)

One of the most striking external differences between the older and new forms of the Roman Rite concerns the music. Any Catholic who had been asleep from, say, 1960 to 1980 would have woken up to a completely different world, one that seemed to welcome pop styles at Mass and banish Gregorian chant. It is even more shocking to consider that Vatican II contained the most explicit and canonically binding recognition in the history of Christianity that Gregorian chant is the music of the Roman Rite.
In trying to come to terms with what happened, there are three general theories about the true musical intentions of the Second Vatican Council, one of which gains new credibility in a new book by Anthony Ruff, Sacred Music and Liturgical Reform: Treasures and Transformations (Chicago: Liturgy Training Publications, 2007).
The first position we can describe as the progressive position, namely that the Constitution on the Sacred Liturgy intended to unleash a furious reform of the Roman Rite in which the vernacular took over, chant was banished because it is boring and in Latin, and the people took power back from the clerical class. In this view, it’s true that this was not in the letter of the law but it was part of the “spirit” of the reform. The 1970 Missal, too, was part of the spirit but not its completion. What we needed, in this view, were creative liturgists to take ever more liberties to make the Mass community-minded and accessible, in touch with the modern world. Hence the guitars, dancers, puppet shows, and textual improvisations.
On the other side of the debate are those who we might call the traditionalists, who oddly suspect that the progressives are largely correct. The Constitution contained ticking time bombs which people at the Council put into the friendly to tradition is really only tactical. What was secretly intended was the furious reform that actually took place.
Where these two positions agree is that the manner in which the liturgy is celebrated in the ordinary form represents, in some way, a fulfillment of the Council’s intentions. Where these positions disagree is whether this is a good thing or not. The progressives love it while the traditionalists say that it is a disgrace and the only solution is full restoration of the 1962 Missal, the last Missal to appear before the 1963 Constitution unleashed this “spirit of Vatican II” that ended up unraveling the Roman Rite as it has always been known.
A third position has occupied a tiny minority of opinion over the years, and yet it is gaining prominence today in light of the call for greater continuity between old and new. For convenience we can call it the conservative view. (Please don’t get stuck on the terms here; they are only placeholders for general tendencies of thought.)
This is the position that when the Constitution spoke with praise for Gregorian chant and polyphony, it was speaking truthfully and clearly with the intention of giving them an increased presence in the liturgy. Further, though the 1970 Missal has its problems and issues, if it is said according to the liturgical books, and the dictates of Vatican II are followed, what you end up with is something that is much more organic to tradition. You have Latin chant for the ordinary and the propers. You have the Mass said with the solemnity of old, whether in Latin or in English. This was the true intention of the Council, according to this view.

(Jeffrey A. Tucker, Sing like a Catholic, pp. 16-17)

The chant of the Propers is an integral part of the classical Roman liturgy: in fact, it was one of the first elements to be crystallized during its early development. Its position was so stable, so ‘canonized’, that it hardly developed further after the eighth century, except in one single genre, the Alleluia chant. Theologically, the selection of the chant texts (mostly from psalms) was built on a traditional biblical interpretation that can be traced to the sayings of Christ and his Apostles. This interpretation was supplied with an expanded explanation in the enarrationes of Origen and St Augustine of Hippo. Out of this tradition of interpretation a system of associations arose between the biblical and psalmic texts together with the other parts of the liturgy. To omit the chants of the Propers from any celebration of the Roman Mass – even if they are at least recited – is an inexcusable mutilation of the Roman Rite in itself.

(László Dobszay, The Restoration and Organic Development of the Roman Rite, p. 159)