CathInfo.com

Elsewhere I have written:

«Citing the work of Da Silveira, Don Curzio Nitoglia explains that the first opinion, that a pope cannot be a heretic, is the one that is most commonly taught as the most probable by the majority of theologians and Doctors: Bellarmine, Francisco Suárez, Melchior Cano, Domingo Soto, John of St. Thomas, Juan de Torquemada, Louis Billot, Joachim Salaverri, A. Maria Vellico, Charles Journet (and Cajetan who is not cited by Da Silveira, but is demonstrated by Msgr. Vittorio Mondello in La dottrina del Gaetano sul Romano Pontefice, Messina, Istituto Arti Grafiche di Sicilia, 1965, cap. V, pp. 163-194 e cap. VI, pp. 195-224). ... Bordoni, who held the opinion to be “very probable”, cites Suárez, Pedro de Simanca, Domingo Bañez, and Bellarmine to be of this opinion; and mentions that Bonacina, cites others who were of the same opinion, explaining that they (as well as he) based their opinion on the belief that the words, Ut non deficiat fides tua were spoken simpliciter, and therefore without distinction between the public or the private person. Bordoni also argued extensively on the notable disputed cases proving that none of those popes was a formal heretic. [...] Opinion No. 1 is founded on the words of Christ Himself who prayed that the Pontiff’s faith not fail. Pope Innocent III and St. Robert Bellarmine based their teaching that the pope cannot become a heretic on the foundation of that scripture passage. Since Vatican I taught on the basis of that passage that the grace is given to the pope lest his fail, precisely so that he may be able to define infallibly; the First Opinion, namely, that the pope cannot fall into formal heresy, has become “commonly taught as the most probable”, as Don Curzio attests. Fr Gleize states on the question, “Can a pope fall into heresy?”: “In fact, the negative answer to this question is the common opinion of theologians of the modern era.” However, in order to deceive their readers into believing that their contrary opinion represents the mind of the Church, and seduce them into thinking the opposite opinion is the common opinion, Salza & Siscoe falsely state on page 191 of their screed: “It is the common opinion among theologians that a Pope can fall into personal heresy (internally), and even public and notorious heresy (externally).”»         

Sources and links are provided in my book, To Deceive the Elect, Volume One. Don Curzio in the cited passage treats of a specific point of doctrine, to wit, that the common opinion of theoligians is that a valid pope cannot be a formal heretic. The article is posted on his website. He has not deviated from this position; and whether or not he has changed his position as a sedeprivationist is totally irrelevant to this point of doctrine.