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.