Edward Feser is a philosopher not a historian, but he reminds us of a piece of Catholic history that the powers that currently be within the Church seek to ignore:
The Church has for centuries allowed among theologians free discussion of the possibility of a heretical pope. Cajetan, Suarez, and Bellarmine are among the eminent theologians who have entertained this possibility and debated its ramifications. (Canon lawyer Ed Peters offers a primer on the matter.) Once again to quote the Catholic Encyclopedia:
[An] exceptional situation might arise were a pope to become a public heretic, i.e., were he publicly and officially to teach some doctrine clearly opposed to what has been defined as de fide catholicâ… [I]n this case many theologians hold that no formal sentence of deposition would be required, as, by becoming a public heretic, the pope would ipso facto cease to be pope. This, however, is a hypothetical case which has never actually occurred…
In an earlier post I discussed in some detail the conditions under which a pope speaks infallibly, the many ways a pope may fall into error when his words do not meet those conditions, and many further examples of popes who have fallen into error and done grave damage to the Church. As I there emphasized, one cannot properly understand the authority of the pope and the doctrine of papal infallibility unless one also understands the limits of papal authority and the ways in which a pope is fallible.
I have quoted extensively from the 1910 Catholic Encyclopedia for a reason. There is a certain kind of well-meaning but overzealous and under-informed Catholic whose theological horizon does not extend beyond the debates that have riven the Church since Vatican II. When you tell him that it is possible for a pope to fall into doctrinal error, his hackles rise and he assumes that you simply must be either a Lefebvrist traditionalist or a dissenting theological liberal. As the example of the Catholic Encyclopedia shows, nothing could be further from the truth. The Encyclopedia predated by many decades Vatican II and the progressive and traditionalist movements that arose in reaction to it. It was an ecclesiastically approved work by mainstream Catholic scholars loyal to the Magisterium, and intended to be a reliable resource for the faithful. And it quite matter-of-factly allows for the possibility of popes committing doctrinal errors when not speaking ex cathedra.
Nor is the possibility of correction of the pope by his subordinates some post-Vatican II progressive or traditionalist novelty. As Cardinal Raphael Merry del Val wrote in his 1902 book The Truth of Papal Claims, responding to caricatures of the doctrine of papal infallibility:
Great as our filial duty of reverence is towards what ever [the pope] may say, great as our duty of obedience must be to the guidance of the Chief Shepherd, we do not hold that every word of his is infallible, or that he must always be right. (p. 19)
After noting that St. Paul “had resisted even Peter” and then recounted this resistance in the Letter to the Galatians, the cardinal says:
[E]ven to-day a Bishop might… expostulate with a Pope, who, in his judgment, might be acting in a way which was liable to mislead those under his own charge, and then write to his critics that he had not hesitated to pass strictures upon the action of the successor of S. Peter… The hypothesis is quite conceivable, and in no way destroys or diminishes the supremacy of the Pope. And yet an individual Bishop does not occupy the exceptional position of S. Paul, a fellow-Apostle of the Prince of the Apostles. Even a humble nun, S. Catherine of Siena, expostulated with the reigning Pontiff, in her day, whilst full acknowledging all his great prerogatives. (p. 74)
Go here to read the rest. The Catholic Faith is not simply whatever the Pope of the moment says it is, and Catholics who speak up for the true teaching of the Faith, even in the face of a mistaken Pope, have a glorious history on their side.