“…..it lies within the Church’s power only to judge whether or not a claimant was validly elected, and for that, the Church would have to judge whether or not the claimant was a capable subject of assuming the papacy. Therefore, TWO CORROLARIES FOLLOW BY STRICT LOGICAL NECESSITY: 1) that it is impossible for a true pope to fall into formal heresy, and; 2) a manifest heretic pope is one who can be shown by the fact alone of manifest heresy to have never validly assumed the papacy, nor to have ever legitimately occupied the pontifical office.”
Kramer, Paul. On the true and the false pope: The case against Bergoglio (p. 285). Gondolin Press. Kindle Edition.