Concede the history at once: there have been genuinely wicked popes, men who bought the office, fathered children, ordered killings. The tenth century alone is a catalogue of them. But notice what the objection quietly assumes, that papal authority rests on papal holiness. It does not, and the Church has never said it did. The doctrine is infallibility, not impeccability: protection from teaching error when defining the faith, not protection from personal sin.

Look at what Christ actually promised Peter. Not sinlessness, in the very same breath He foretold Peter’s threefold denial. What He promised was this: “I have prayed for thee, that thy faith fail not: and thou, being once converted, confirm thy brethren” (Luke 22:32). The guarantee attaches to the faith Peter hands on, not to his courage, his virtue, or his private life. Peter denied Christ within hours of that promise, and was still the rock.

Christ had already stated the principle about the chair of Moses. The scribes were corrupt, yet He instructed: “All things therefore whatsoever they shall say to you, observe and do; but according to their works do ye not” (Matthew 23:2–3). The authority of the seat holds even when the man in it is a hypocrite. And here is the startling historical fact: across the very centuries when the worst men held the office, not one of them ever taught heresy ex cathedra. They sinned in every other way imaginable; they never corrupted the deposit of faith.2

There is something almost evidential in that restraint. A purely human institution led by such men, for so long, would eventually have rationalized its corruption into doctrine, blessed the mistresses, declared the simony sound. The papacy never did; the sins of churchmen stood condemned by the very faith those churchmen were bound to teach. So a bad pope is precisely what the doctrine says is survivable: a sinner in Peter’s chair, answerable to the truth he could not unmake, and which, against every human odds, went unmarred.