Liturgy of St Pius V "Set in Stone"?

A very useful column by Fr Edward McNamara in the Liturgy Questions section on the Zenit site. A reader asks why, when Pope St. Pius V "set in stone for all time the exactness of the holy sacrifice of the Mass to be said in the mother tongue of the Church", future Popes (eg. Paul VI) could dare to make changes. Fr McNamara makes good sense of this difficult question, defending the authority of the Bishop of Rome to make changes to the Liturgy.

For a start, he shows that changes were made to the liturgy even by St Pius V himself after the promulgation of his bull Quo Primum. He says:

Likewise, legal expressions such as "which shall have the force of law in perpetuity, We order and enjoin under pain of Our displeasure that nothing be added to Our newly published Missal, nothing omitted therefrom, and nothing whatsoever altered therein" cannot be literally interpreted as binding on possible later actions of Pope St. Pius V or upon his successors. The strictures fall only upon those who act without due authority.

If it were otherwise, then Pope St. Pius V would have excommunicated himself a couple of years after publishing "Quo Primum" when he added the feast of Our Lady of the Rosary to the missal following the Battle of Lepanto in 1571, not to mention Pope Clement XI who canonized Pius V in 1712, thus altering the missal.

Among the many other Popes who would have thus incurred "the wrath of Almighty God and of the blessed Apostles Peter and Paul" would have been St. Pius X for reforming the calendar, Pius XI who added the first new preface in centuries for the feast of Christ the King, Pius XII for completely revamping the rites of Holy Week as well as simplifying the rubrics, and Blessed John XXIII for adding St. Joseph's name to the Roman Canon.

Certainly, the reform undertaken under the Servant of God Pope Paul VI ranged more widely than anything done under earlier Popes since St. Pius V. But Paul VI acted with the same papal authority as all of them.

Fr McNamara's final comment is:

It is for this reason that, except in matters of faith and morals, a pope's disciplinary decrees in matters such as the non-essential elements of liturgical rites are never "set in stone" and can be changed by a subsequent Supreme Pontiff whenever he believes that the duty of feeding Christ's flock requires it.