If you decide, in all sincerity, after careful consideration and prayer, in good conscience, that Pope Francis is a heretic and therefore you can no longer offer to God your holy submission to the Supreme Pontiff, nor remain in communion with the Bishops of the Church subject to him, then you have committed the grave sin of formal schism.
It does not matter that you are in good conscience, sincerely believing that you are right and the Pope is wrong. It does not matter that you have prayed fervently and at great length about this matter. It does not matter that your objective mortal sin in rejecting the Pope is not an actual mortal sin, due to your mistaken but sincere conscience. The act of formal schism only requires that you act with knowledge and deliberation: that you understand well the choice you are making, and that you act with full freedom of choice. You might still be in a state of grace, but you are no longer a formal member of the Church.
You might argue that Pope Francis has ceased to be a formal member of the Church, having cut himself off from the one true Church and the true Faith by the sin of heresy. But under Church teaching and Church law, by rejecting the Pope, you have cut yourself off from the Church by the sin of formal schism. For everyone who commits apostasy, or formal heresy, or formal schism is excommunicated latae sententiae (automatically).
Can. 751 Heresy is the obstinate denial or obstinate doubt after the reception of baptism of some truth which is to be believed by divine and Catholic faith; apostasy is the total repudiation of the Christian faith; schism is the refusal of submission to the Supreme Pontiff or of communion with the members of the Church subject to him.
Canon 1364 §1: an apostate from the faith, a heretic, or a schismatic incurs a latae sententiae excommunication.
It is sadly ironic that some Catholics have cut themselves off from the Church by falsely accusing the Pope of having cut himself off from the Church. They say that the Pope has ceased to be a member of the Church, but by this rejection of the Pope, they themselves have ceased to be formal members of the Church.
Jesus taught the indefectibility of the Church, that the Church cannot fail by going astray, and that Peter and his successors are the Rock on which the indefectibility of the Church is founded (Mt 16:17-19). So by accusing the Pope of heresy, you have accused Jesus of lying and of failing to protect His Church. Neither can you argue that the Church remains indefectible, since only the Pope has gone astray; for the body of Bishops throughout the world continue to remain in communion with the Pope. If the Pope commits heresy and the Bishops continue to support him, then either the whole Church has departed from the true Faith, or YOU ARE THE ONE WHO HAS GONE ASTRAY!! But in your pride, you assume that you yourself could not have erred.
In my understanding, no Pope can ever commit apostasy or heresy or schism, because the grace of God absolutely prevents it, for the sake of the Church and the faithful. Thou shalt not bear False Witness against the Pope
And if you argue that various Saints and Doctors said that the Pope can commit heresy, my response is that the opinions of Saints and Doctors is subject to the teaching of the Magisterium. Saint Thomas erred in the Summa Theologica on the Immaculate Conception. The Magisterium, at a later time, definitely decided the question in contradiction to his opinion. And we are not free, today, to hold his opinion, even though he is a Saint and Doctor. We are subject to the authority of the Pope and the Bishops, just as he was.
And no Saint or Doctor has ever accused any Pope of heresy. Some wrote about the mere hypothetical case, what if the Pope committed heresy. But none ever made such an accusation, as some ignorant and arrogant Catholics have done today. What Saint Bellarmine really said about Popes and Heresy
Everyone in a state of grace is a member of the one true Church, at least implicitly. But apostates, heretics, and schismatics are no longer formal members of the Church, even if they depart from the Church in sincere but mistaken conscience.
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