[american colleen]

And remember, Vatican I was explicit in stating that the Holy Spirit did not protect papal novelties from error.

And what guides us, as Catholics, to have the grace to know from "papal novelties" (which would be what, btw?)?

Martin Luther thought he knew by the grace of God.
John Calvin thought he knew by the grace of God.
Richard Hooker thought he knew by the grace of God.
John Knox thought he knew by the grace of God.

Ya know what I mean?

[ultima ratio]

A novelty obviously means whatever is new--not handed-down. Most innovations are innocuous--but some are doctrinal and liturgical and constitute important breaks with tradition which should set off alarm bells among the faithful. Assisi was one example. The new doctrine on the Jews is another. Both are radical departures.

Remember, Luther and Calvin and Hooker and Knox were introducing novelties, not sticking with tradition. So your lumping Catholic traditionalists with them is a poor analogy. Rather we resemble the followers of Saint Athanasius who defied his pope to follow Catholic tradition rather than the Arianism that ruled the Church of his day.