The number and the weight of the theological authorities support the contention that a pope who committed a public and notorious act of heresy would automatically cease to be pope. The authors tell us that it is the “most common” teaching of the canonists and theologians; three doctors of the Church have taught it, none have taught contrary; the canonized theologians are unanimous; Bellarmine wrote that “this is the opinion of all the ancient Fathers”. We shall consider the conditions for public and notorious heresy below.
Saint Antoninus (1389-1459): “In the case in which the pope would become a heretic, he would find himself, by that fact alone and without any other sentence, separated from the Church. A head separated from a body cannot, as long as it remains separated, be head of the same body from which it was cut off. A pope who would be separated from the Church by heresy, therefore, would by that very fact itself cease to be head of the Church. He could not be a heretic and remain pope, because, since he is outside of the Church, he cannot possess the keys of the Church.” (Summa Theologica. Quoted in Actes de Vatican I.)
Saint Robert Bellarmine, Doctor (1542-1621): “Therefore, the true opinion is the fifth, according to which the Pope who is manifestly a heretic ceases by himself to be Pope and head, in the same way as he ceases to be a Christian and a member of the body of the Church; and for this reason he can be judged and punished by the Church. This is the opinion of all the ancient Fathers, who teach that manifest heretics immediately lose all jurisdiction, and outstandingly that of St. Cyprian (lib. 4, epist. 2) who speaks as follows of Novatian, who was Pope [i.e. antipope] in the schism which occurred during the pontificate of St. Cornelius: ‘He would not be able to retain the episcopate [i.e. of Rome], and, if he was made bishop before, he separated himself from the body of those who were, like him, bishops, and from the unity of the Church.’ According to what St. Cyprian affirms in this passage, even had Novatian been the true and legitimate Pope, he would have automatically fallen from the pontificate, if he separated himself from the Church.
“This is the opinion of great recent doctors, as John Driedo (lib. 4 de Script. et dogmat. Eccles., cap. 2, par. 2, sent. 2), who teaches that only they separate themselves from the Church who are expelled, like the excommunicated, and those who depart by themselves from her or oppose her, as heretics and schismatics. And in his seventh affirmation, he maintains that in those who turn away from the Church, there remains absolutely no spiritual power over those who are in the Church. Melchior Cano says the same (lib. 4 de loc., cap. 2), teaching that heretics are neither parts nor members of the Church, and that it cannot even be conceived that anyone could be head and Pope, without being member and part (cap. ult. ad argument. 12). And he teaches in the same place, in plain words, that occult heretics are still of the Church, they are parts and members, and that therefore the Pope who is an occult heretic is still Pope. This is also the opinion of the other authors whom we cite in book I De Ecclesia.
“The foundation of this argument is that the manifest heretic is not in any way a member of the Church, that is, neither spiritually nor corporally, which signifies that he is not such by internal union nor by external union. For even bad Catholics [i.e. who are not heretics] are united and are members, spiritually by faith, corporally by confession of faith and by participation in the visible sacraments; the occult heretics are united and are members although only by external union; on the contrary, the good catechumens belong to the Church only by an internal union, not by the external; but manifest heretics do not pertain in any manner, as we have already proved.” (De Romano Pontifice, lib. II, cap. 30.)
Saint Frances de Sales, Doctor (1567-1622): “Now when [the Pope] is explicitly a heretic, he falls ipso facto from his dignity and out of the Church, and the Church must either deprive him, or, as some say [better], declare him deprived, of his Apostolic See.” (The Catholic Controversy.)
Saint Alphonsus Maria Liguori, Doctor (1696-1787): “If, however, God were to permit a pope to become a notorious and contumacious heretic, he would by such a fact cease to be pope, and the apostolic chair would be vacant.” (Verita della Fede, III, VIII. 9-10.)
Cardinal Billot (1846-1931): “Once the hypothesis that a Pope can become a known and public heretic is conceded as a possibility, it would follow that it must be admitted without hesitation that such a Pope would ipso facto lose his papal authority since, in betraying the faith, he would by his own will, have separated himself from the body of the Church.”
J. Wilhelm: “The pope himself, if notoriously guilty of heresy, would cease to be pope because he would cease to be a member of the Church.”(Heresy, 1914 Catholic Encyclopedia)
Code of Canon Law of 1917. Canon 188: “Through tacit resignation, accepted by the law itself, all offices become vacant ipso facto and without any declaration if a cleric: … #4) has publicly forsaken the Catholic faith.”
Caesar Badii: “Cessation of pontifical power. This power ceases: […] (d) Through notorious and openly divulged heresy. A publicly heretical pope would no longer be a member of the Church; for this reason, he could no longer be its head.” (Institutiones Iuris Canonici. Florence: Fiorentina 1921. 160, 165.)
Dominic Prummer: “The power of the Roman Pontiff is lost. […] (c) By his perpetual insanity or by formal heresy. And this at least probably. […] The Authors indeed commonly teach that a pope loses his power through certain and notorious heresy, but whether this case is really possible is rightly doubted.” (Manuale Iuris Canonci. Freiburg im Briesgau: Herder 1927. 95.)
F.X. Wernz, P. Vidal: “Finally, there is the fifth opinion – that of Bellarmine himself – which was expressed initially and is rightly defended by Tanner and others as the best proven and the most common. For he who is no longer a member of the body of the Church, i.e. the Church as a visible society, cannot be the head of the Universal Church. But a Pope who fell into public heresy would cease by that very fact to be a member of the Church. Therefore he would also cease by that very fact to be the head of the Church. Indeed, a publicly heretical Pope, who, by the commandment of Christ and the Apostle must even be avoided because of the danger to the Church, must be deprived of his power as almost all admit.” (Ius Canonicum. Rome: Gregorian 1943. 2:453.)
Udalricus Beste: “Not a few canonists teach that, outside of death and abdication, the pontifical dignity can also be lost by falling into certain insanity, which is legally equivalent to death, as well as through manifest and notorious heresy. In the latter case, a pope would automatically fall from his power, and this indeed without the issuance of any sentence, for the first See is judged by no one. The reason is that, by falling into heresy, the pope ceases to be a member of the Church. He who is not a member of a society, obviously cannot be its head.” (Introductio in Codicem. 3rd ed. Collegeville: St John’s Abbey Press 1946. Canon 221.)
A. Vermeersch, I. Creusen: “The power of the Roman Pontiff ceases by death, free resignation (which is valid without need for any acceptance, c.221), certain and unquestionably perpetual insanity and notorious heresy. At least according to the more common teaching, the Roman Pontiff as a private teacher can fall into manifest heresy. Then, without any declaratory sentence (for the supreme See is judged by no one), he would automatically fall from a power which he who is no longer a member of the Church is unable to possess.” (Epitome Iuris Canonici. Rome: Dessain 1949. 340.)
Matthaeus Conte a Coronata: “2. Loss of office of the Roman Pontiff. This can occur in various ways: […] c) Notorious heresy. Certain authors deny the supposition that the Roman Pontiff can become a heretic. It cannot be proven however that the Roman Pontiff, as a private teacher, cannot become a heretic – if, for example, he would contumaciously deny a previously defined dogma. Such impeccability was never promised by God. Indeed, Pope Innocent III expressly admits such a case is possible. If indeed such a situation would happen, he would, by divine law, fall from office without any sentence, indeed, without even a declaratory one. He who openly professes heresy places himself outside the Church, and it is not likely that Christ would preserve the Primacy of His Church in one so unworthy. Wherefore, if the Roman Pontiff were to profess heresy, before any condemnatory sentence (which would be impossible anyway) he would lose his authority.” (Institutiones Iuris Canonici. Rome: Marietti 1950. I:3I2, 3I6.)
Donald Attwater: “A pope can only be deposed for heresy, expressed or implied, and then only by a general council. It is not strictly deposition, but a declaration of fact, since by his heresy he has already ceased to be head of the Church. […] An heretical pope necessarily ceases to be head of the Church, for by his heresy he is no longer a member thereof: in the event of his still claiming the Roman see a general council, improperly so-called because without the pope, could remove him. But this is not deposition, since by his own act he is no longer pope.” (A Catholic Dictionary 1951)
Eduardus F. Regatillo: “The Roman Pontiff ceases in office: […] (4) Through notorious public heresy? Five answers have been given: 1. ‘The pope cannot be a heretic even as a private teacher.’ A pious thought, but essentially unfounded. 2. ‘The pope loses office even through secret heresy.’ False, because a secret heretic can be a member of the Church. 3. ‘The pope does not lose office because of public heresy.’ Objectionable. 4. ‘The pope loses office by a judicial sentence because of public heresy.’ But who would issue the sentence? The See of Peter is judged by no one (Canon 1556). 5. ‘The pope loses office ipso facto because of public heresy.’ This is the more common teaching, because a pope would not be a member of the Church, and hence far less could be its head.” (Institutiones Iuris Canonici. 5th ed. Santander: Sal Terrae, 1956. 1:396.)
Serapius Iragui: “For this reason, theologians commonly concede that the Roman Pontiff, if he should fall into manifest heresy, would no longer be a member of the Church, and therefore could neither be called its visible head.” (Manuale Theologiae Dogmaticae. Madrid: Ediciones Studium 1959.)