In this post, I discussed the limits of Papal authority as regards the sacred liturgy and tradition. I argued that in the tradition of the Church, it was never assumed that the Pope had the authority to depart from or overthrow any of the legitimate traditions of the Church. But I think a slight correction is in order. Although we might speak of the Pope's authority as being subject to tradition, I think that, strictly speaking, we might have to admit that the Pope does indeed possess the authority, at least in theory, to abandon a (small-t) tradition of the Church. I believe Michael Davies discusses this point, and he gives an analogy that might be helpful here: for example, the Pope may indeed have the legal authority to demolish the great Basilica of St. Peter, which can be said to be a part of the tradition of the Church (small-t tradition). Further, the Pope might erect in place of it a hideous glass building of some sort. But this does not mean that the Pope would have the moral right to do so; on the contrary, there is very strong case to be made that he does not have such a right, and even further, that he has a moral duty not to do so, simply on the basis of tradition.
Similarly, the Pope might well have the authority to completely overthrow the liturgical traditions of the Church and replace them with something completely novel. But this does not mean that he would have the right to do so. Indeed, it would be just as easy to make the case that he has a duty not to do so, simply on the basis of tradition. This at least, I think, is evident from the constant and common consent of the Catholic fathers, doctors, theologians and faithful, down through the history of the Church, as I argued in the other post. Basically, then, the Pope does not have the right to rewrite the rite. (Fun way of putting it, that.)
The difference between these two terminologies is a real and significant difference. I think it might be said that the authority, strictly speaking, of the Pope, is founded upon the divine constitution of the Church, from which it is impossible for the Pope to depart. This is the doctrine of the indefectibility of the Church. The Pope could not ever depart from the authority, in the strictest sense of it, granted him by God. But this is not incompatible with the claim that he could depart from the moral duties imposed upon him in the having of that very same authority. One of those moral duties is the preservation of the Church's traditions, particularly in matters pertaining to the sacred liturgy.
Another consequence of this clarification is that the Novus Ordo, though indeed something which is problematic in many aspects, is still a legitimate liturgy, having been established within all the legal bounds which accompany the authority of the Pope. But this is not to admit that is establishment within the Church was not a departure from the moral limits to which Catholics, particularly the Pope, are bound.
Although this difference is real and significant, insofar as it touches the very foundational principles of the Catholic faith, nonetheless in practice there would seem to be but little change in the life of the Church. Catholics must all still uphold the traditions of the Church, particularly in matters of liturgy; and this is still true of the Pope as well as of all those under his jurisdiction. And that is the essential point made by traditionalists, however much they might disagree about the other concepts which relate to this problem. So my essential position is unchanged; but I do think it is important to get things like this straight.