Thanks to New Catholic at Rorate Caeli for the links and translations. I've added emphasis only to the passages where I think it's obvious that the proverbial rubber hits the road.
First is the Summorum Pontificum, then is the Papal Explanatory Letter.
APOSTOLIC LETTER SUMMORUM PONTIFICUM OF THE SUPREME PONTIFF BENEDICT XVI GIVEN MOTU PROPRIO
[INTRODUCTION: Unofficial Vatican Information Service Translation, amended where needed]
It has been the constant concern of the Supreme Pontiffs, and up to the present time, to ensure that the Church of Christ offers a worthy ritual to the Divine Majesty, 'to the praise and glory of His name,' and 'to the benefit of all His Holy Church.'
Since time immemorial it has been necessary - as it is also for the future - to maintain the principle according to which 'each particular Church must concur with the universal Church, not only as regards the doctrine of the faith and the sacramental signs, but also as regards the usages universally accepted by uninterrupted apostolic tradition, which must be observed not only to avoid errors but also to transmit the integrity of the faith, because the Church's law of prayer corresponds to her law of faith.' (1)
Among the pontiffs who showed that requisite concern, particularly outstanding is the name of St. Gregory the Great, who made every effort to ensure that the new peoples of Europe received both the Catholic faith and the treasures of worship and culture that had been accumulated by the Romans in preceding centuries. He commanded that the form of the sacred liturgy as celebrated in Rome (concerning both the Sacrifice of Mass and the Divine Office) be conserved. He took great concern to ensure the dissemination of monks and nuns who, following the Rule of St. Benedict, together with the announcement of the Gospel illustrated with their lives the wise provision of their Rule that 'nothing should be placed before the work of God.' In this way the sacred liturgy, celebrated according to the Roman use, enriched not only the faith and piety but also the culture of many peoples. It is known, in fact, that the Latin liturgy of the Church in its various forms, in each century of the Christian era, has been a spur to the spiritual life of many saints, has reinforced many peoples in the virtue of religion and fecundated their piety.
Many other Roman pontiffs, in the course of the centuries, showed particular solicitude in ensuring that the sacred liturgy accomplished this task more effectively. Outstanding among them is St. Pius V who, sustained by great pastoral zeal and following the exhortations of the Council of Trent, renewed the entire liturgy of the Church, oversaw the publication of liturgical books amended and 'renewed in accordance with the norms of the Fathers,' and provided them for the use of the Latin Church.
One of the liturgical books of the Roman rite is the Roman Missal, which developed in the city of Rome and, with the passing of the centuries, little by little took forms very similar to that it has had in recent times.
'It was towards this same goal that succeeding Roman Pontiffs directed their energies during the subsequent centuries in order to ensure that the rites and liturgical books were brought up to date and when necessary clarified. From the beginning of this century they undertook a more general reform.' (2) Thus our predecessors Clement VIII, Urban VIII, St. Pius X (3), Benedict XV, Pius XII and Blessed John XXIII all played a part.
In more recent times, Vatican Council II expressed a desire that the respectful reverence due to divine worship should be renewed and adapted to the needs of our time. Moved by this desire our predecessor, the Supreme Pontiff Paul VI, approved, in 1970, reformed and partly renewed liturgical books for the Latin Church. These, translated into the various languages of the world, were willingly accepted by bishops, priests and faithful. John Paul II amended the third typical edition of the Roman Missal. Thus Roman pontiffs have operated to ensure that 'this kind of liturgical edifice ... should again appear resplendent for its dignity and harmony.' (4)
But in some regions, no small numbers of faithful adhered and continue to adhere with great love and affection to the earlier liturgical forms. These had so deeply marked their culture and their spirit that in 1984 the Supreme Pontiff John Paul II, moved by a concern for the pastoral care of these faithful, with the special indult 'Quattuor abhinc anno," issued by the Congregation for Divine Worship, granted permission to use the Roman Missal published by Blessed John XXIII in the year 1962. Later, in the year 1988, John Paul II with the Apostolic Letter given as Motu Proprio, 'Ecclesia Dei,' exhorted bishops to make generous use of this power in favor of all the faithful who so desired.
[ONLY LEGAL ARTICLES OFFICIALLY TRANSLATED]
Our predecessor John Paul II having already considered the insistent petitions of these faithful, having listened to the views of the Cardinal Fathers of the Consistory of 22 March 2006, having reflected deeply upon all aspects of the question, invoked the Holy Spirit and trusting in the help of God, with these Apostolic Letters We establish the following:
Art. 1 The Roman Missal promulgated by Paul VI is the ordinary expression of the Lex orandi (Law of prayer) of the Catholic Church of the Latin rite. Nonetheless, the Roman Missal promulgated by St. Pius V and reissued by Bl. John XXIII is to be considered as an extraordinary expression of that same Lex orandi, and must be given due honour for its venerable and ancient usage. These two expressions of the Church’s Lex orandi will in no any way lead to a division in the Church’s Lex credendi (Law of belief). They are, in fact two usages of the one Roman rite.
It is, therefore, permissible to celebrate the Sacrifice of the Mass following the typical edition of the Roman Missal promulgated by Bl. John XXIII in 1962 and never abrogated, as an extraordinary form of the Liturgy of the Church. The conditions for the use of this Missal as laid down by earlier documents Quattuor abhinc annis and Ecclesia Dei, are substituted as follows:
Art. 2 In Masses celebrated without the people, each Catholic priest of the Latin rite, whether secular or regular, may use the Roman Missal published by Bl. Pope John XXIII in 1962, or the Roman Missal promulgated by Pope Paul VI in 1970, and may do so on any day with the exception of the Easter Triduum. For such celebrations, with either one Missal or the other, the priest has no need for permission from the Apostolic See or from his Ordinary.
Art. 3 Communities of Institutes of consecrated life and of Societies of apostolic life, of either pontifical or diocesan right, wishing to celebrate Mass in accordance with the edition of the Roman Missal promulgated in 1962, for conventual or “community” celebration in their oratories, may do so. If an individual community or an entire Institute or Society wishes to undertake such celebrations often, habitually or permanently, the decision must be taken by the Superiors Major, in accordance with the law and following their own specific decrees and statues.
Art. 4 Celebrations of Mass as mentioned above in art. 2 may – observing all the norms of law – also be attended by faithful who, of their own free will, ask to be admitted.
Art. 5 § 1 In parishes, where there is a stable group of faithful who adhere to the earlier liturgical tradition, the pastor should willingly accept their requests to celebrate the Mass according to the rite of the Roman Missal published in 1962, and ensure that the welfare of these faithful harmonises with the ordinary pastoral care of the parish, under the guidance of the bishop in accordance with canon 392, avoiding discord and favouring the unity of the whole Church.
§ 2 Celebration in accordance with the Missal of Bl. John XXIII may take place on working days; while on Sundays and feast days one such celebration may also be held.
§ 3 For faithful and priests who request it, the pastor should also allow celebrations in this extraordinary form for special circumstances such as marriages, funerals or occasional celebrations, e.g. pilgrimages.
§ 4 Priests who use the Missal of Bl. John XXIII must be qualified to do so and not juridically impeded.
§ 5 In churches that are not parish or conventual churches, it is the duty of the Rector of the church to grant the above permission.
Art. 6 In Masses celebrated in the presence of the people in accordance with the Missal of Bl. John XXIII, the readings may be given in the vernacular, using editions recognised by the Apostolic See.
Art. 7 If a group of lay faithful, as mentioned in art. 5 § 1, has not obtained satisfaction to their requests from the pastor, they should inform the diocesan bishop. The bishop is strongly requested to satisfy their wishes. If he cannot arrange for such celebration to take place, the matter should be referred to the Pontifical Commission “Ecclesia Dei”.
Art. 8 A bishop who, desirous of satisfying such requests, but who for various reasons is unable to do so, may refer the problem to the Commission “Ecclesia Dei” to obtain counsel and assistance.
[I'm concerned over Articles 7 & 8. I can easily forsee this happening - if any given pastor refuses to celebrate the TLM for a "group of lay faithful", that same group can inform the local bishop. If that particular bishop decides to take no action enforcing this particular motu proprio, all that bishop has to do is forward it to the Ecclesia Dei Commission. From there, it'll die of loneliness. I have a nasty feeling that THIS is the loophole that priests and bishops who are hostile to the Latin Mass will use to squash it.]
Art. 9 § 1 The pastor, having attentively examined all aspects, may also grant permission to use the earlier ritual for the administration of the Sacraments of Baptism, Marriage, Penance, and the Anointing of the Sick, if the good of souls would seem to require it.
§ 2 Ordinaries are given the right to celebrate the Sacrament of Confirmation using the earlier Roman Pontifical, if the good of souls would seem to require it.
§ 2 Clerics ordained “in sacris constitutis” may use the Roman Breviary promulgated by Bl. John XXIII in 1962.
Art. 10 The ordinary of a particular place, if he feels it appropriate, may erect a personal parish in accordance with can. 518 for celebrations following the ancient form of the Roman rite, or appoint a chaplain, while observing all the norms of law. [In other words, a Bishop can erect a Latin Mass only parish if he so desires]
Art. 11 The Pontifical Commission “Ecclesia Dei”, erected by John Paul II in 1988, continues to exercise its function. Said Commission will have the form, duties and norms that the Roman Pontiff wishes to assign it.
Art. 12 This Commission, apart from the powers it enjoys, will exercise the authority of the Holy See, supervising the observance and application of these dispositions.
We order that everything We have established with these Apostolic Letters issued as Motu Proprio be considered as “established and decreed”, and to be observed from 14 September of this year, Feast of the Exaltation of the Cross, whatever there may be to the contrary.
From Rome, at St. Peter’s, 7 July 2007, third year of Our Pontificate.
My dear Brother Bishops,
With great trust and hope, I am consigning to you as Pastors the text of a new Apostolic Letter "Motu Proprio data" on the use of the Roman liturgy prior to the reform of 1970. The document is the fruit of much reflection, numerous consultations and prayer.
News reports and judgments made without sufficient information have created no little confusion. There have been very divergent reactions ranging from joyful acceptance to harsh opposition, about a plan whose contents were in reality unknown.
This document was most directly opposed on account of two fears, which I would like to address somewhat more closely in this letter.
In the first place, there is the fear that the document detracts from the authority of the Second Vatican Council, one of whose essential decisions – the liturgical reform – is being called into question. This fear is unfounded. In this regard, it must first be said that the Missal published by Paul VI and then republished in two subsequent editions by John Paul II, obviously is and continues to be the normal Form – the Forma ordinaria – of the Eucharistic Liturgy. The last version of the Missale Romanum prior to the Council, which was published with the authority of Pope John XXIII in 1962 and used during the Council, will now be able to be used as a Forma extraordinaria of the liturgical celebration. It is not appropriate to speak of these two versions of the Roman Missal as if they were "two Rites". Rather, it is a matter of a twofold use of one and the same rite.
As for the use of the 1962 Missal as a Forma extraordinaria of the liturgy of the Mass, I would like to draw attention to the fact that this Missal was never juridically abrogated and, consequently, in principle, was always permitted. At the time of the introduction of the new Missal, it did not seem necessary to issue specific norms for the possible use of the earlier Missal. Probably it was thought that it would be a matter of a few individual cases which would be resolved, case by case, on the local level. Afterwards, however, it soon became apparent that a good number of people remained strongly attached to this usage of the Roman Rite, which had been familiar to them from childhood. This was especially the case in countries where the liturgical movement had provided many people with a notable liturgical formation and a deep, personal familiarity with the earlier Form of the liturgical celebration. We all know that, in the movement led by Archbishop Lefebvre, fidelity to the old Missal became an external mark of identity; the reasons for the break which arose over this, however, were at a deeper level. Many people who clearly accepted the binding character of the Second Vatican Council, and were faithful to the Pope and the Bishops, nonetheless also desired to recover the form of the sacred liturgy that was dear to them. This occurred above all because in many places celebrations were not faithful to the prescriptions of the new Missal, but the latter actually was understood as authorizing or even requiring creativity, which frequently led to deformations of the liturgy which were hard to bear. I am speaking from experience, since I too lived through that period with all its hopes and its confusion. And I have seen how arbitrary deformations of the liturgy caused deep pain to individuals totally rooted in the faith of the Church.
Pope John Paul II thus felt obliged to provide, in his Motu Proprio Ecclesia Dei (2 July 1988), guidelines for the use of the 1962 Missal; that document, however, did not contain detailed prescriptions but appealed in a general way to the generous response of Bishops towards the "legitimate aspirations" of those members of the faithful who requested this usage of the Roman Rite. At the time, the Pope primarily wanted to assist the Society of Saint Pius X to recover full unity with the Successor of Peter, and sought to heal a wound experienced ever more painfully. Unfortunately this reconciliation has not yet come about. Nonetheless, a number of communities have gratefully made use of the possibilities provided by the Motu Proprio. On the other hand, difficulties remain concerning the use of the 1962 Missal outside of these groups, because of the lack of precise juridical norms, particularly because Bishops, in such cases, frequently feared that the authority of the Council would be called into question. Immediately after the Second Vatican Council it was presumed that requests for the use of the 1962 Missal would be limited to the older generation which had grown up with it, but in the meantime it has clearly been demonstrated that young persons too have discovered this liturgical form, felt its attraction and found in it a form of encounter with the Mystery of the Most Holy Eucharist, particularly suited to them. Thus the need has arisen for a clearer juridical regulation which had not been foreseen at the time of the 1988 Motu Proprio. The present Norms are also meant to free Bishops from constantly having to evaluate anew how they are to respond to various situations.
In the second place, the fear was expressed in discussions about the awaited Motu Proprio, that the possibility of a wider use of the 1962 Missal would lead to disarray or even divisions within parish communities. This fear also strikes me as quite unfounded. The use of the old Missal presupposes a certain degree of liturgical formation and some knowledge of the Latin language; neither of these is found very often. Already from these concrete presuppositions, it is clearly seen that the new Missal will certainly remain the ordinary Form of the Roman Rite, not only on account of the juridical norms, but also because of the actual situation of the communities of the faithful.
It is true that there have been exaggerations and at times social aspects unduly linked to the attitude of the faithful attached to the ancient Latin liturgical tradition. Your charity and pastoral prudence will be an incentive and guide for improving these. For that matter, the two Forms of the usage of the Roman Rite can be mutually enriching: new Saints and some of the new Prefaces can and should be inserted in the old Missal. The "Ecclesia Dei" Commission, in contact with various bodies devoted to the usus antiquior, will study the practical possibilities in this regard. The celebration of the Mass according to the Missal of Paul VI will be able to demonstrate, more powerfully than has been the case hitherto, the sacrality which attracts many people to the former usage. The most sure guarantee that the Missal of Paul VI can unite parish communities and be loved by them consists in its being celebrated with great reverence in harmony with the liturgical directives. This will bring out the spiritual richness and the theological depth of this Missal.
I now come to the positive reason which motivated my decision to issue this Motu Proprio updating that of 1988. It is a matter of coming to an interior reconciliation in the heart of the Church. Looking back over the past, to the divisions which in the course of the centuries have rent the Body of Christ, one continually has the impression that, at critical moments when divisions were coming about, not enough was done by the Church’s leaders to maintain or regain reconciliation and unity. One has the impression that omissions on the part of the Church have had their share of blame for the fact that these divisions were able to harden. This glance at the past imposes an obligation on us today: to make every effort to unable for all those who truly desire unity to remain in that unity or to attain it anew. I think of a sentence in the Second Letter to the Corinthians, where Paul writes: "Our mouth is open to you, Corinthians; our heart is wide. You are not restricted by us, but you are restricted in your own affections. In return … widen your hearts also!" (2 Cor 6:11-13). Paul was certainly speaking in another context, but his exhortation can and must touch us too, precisely on this subject. Let us generously open our hearts and make room for everything that the faith itself allows.
There is no contradiction between the two editions of the Roman Missal. In the history of the liturgy there is growth and progress, but no rupture. What earlier generations held as sacred, remains sacred and great for us too, and it cannot be all of a sudden entirely forbidden or even considered harmful. It behooves all of us to preserve the riches which have developed in the Church’s faith and prayer, and to give them their proper place. Needless to say, in order to experience full communion, the priests of the communities adhering to the former usage cannot, as a matter of principle, exclude celebrating according to the new books. The total exclusion of the new rite would not in fact be consistent with the recognition of its value and holiness.
In conclusion, dear Brothers, I very much wish to stress that these new norms do not in any way lessen your own authority and responsibility, either for the liturgy or for the pastoral care of your faithful. Each Bishop, in fact, is the moderator of the liturgy in his own Diocese (cf. Sacrosanctum Concilium, 22: "Sacrae Liturgiae moderatio ab Ecclesiae auctoritate unice pendet quae quidem est apud Apostolicam Sedem et, ad normam iuris, apud Episcopum").
Nothing is taken away, then, from the authority of the Bishop, whose role remains that of being watchful that all is done in peace and serenity. Should some problem arise which the parish priest cannot resolve, the local Ordinary will always be able to intervene, in full harmony, however, with all that has been laid down by the new norms of the Motu Proprio.
Furthermore, I invite you, dear Brothers, to send to the Holy See an account of your experiences, three years after this Motu Proprio has taken effect. If truly serious difficulties come to light, ways to remedy them can be sought.
Dear Brothers, with gratitude and trust, I entrust to your hearts as Pastors these pages and the norms of the Motu Proprio. Let us always be mindful of the words of the Apostle Paul addressed to the presbyters of Ephesus: "Take heed to yourselves and to all the flock, in which the Holy Spirit has made you overseers, to care for the Church of God which he obtained with the blood of his own Son" (Acts 20:28).
I entrust these norms to the powerful intercession of Mary, Mother of the Church, and I cordially impart my Apostolic Blessing to you, dear Brothers, to the parish priests of your dioceses, and to all the priests, your co-workers, as well as to all your faithful.
Given at Saint Peter’s, 7 July 2007
BENEDICTUS PP. XVI