Pertinacity is determined by willfully rejecting the admonitions of the Church. Before Luther's actual excommunication, he was still "Catholic", like it or not.
False. Just because you bloviate "like it or not" ... while ignoring the evidence I cited against it, that doesn't make it true.
Plus you're using terms loosely like "Catholic" ... vs. whether he retained membership in the Church. Once might cease to be Catholic
simpliciter even for occult heresy, vs. membership requires the heresy being manifest.
False that pertinacity requires any kind of formal admonition by the Church, but can happen ipso facto without any such admonition.
So, somone walks around saying, "I don't really care what the Church teaches regarding papal infallbility ... I reject it anyway." That's pertinacity ... no admonition required.
Cajetan would argue that for manifest heresy to result in loss of office or rank within the Church, that would require sentence or declaration. St. Robert Bellarmine held the opposite.
So you you're jumbling up and bumbling and fumbling around terms, conflating things that don't go together.
St. Robert Bellarmine cites the closest thing we have to a Magistrerial position on the matter, from Pope St. Celestine, where he declares that Nestorius had lost authority in the Church from the moment he began preaching his heresy ... despite the fact that his formal condemnation occurred some years later. This he adduces against the position of Cajetan (which you appear to be promoting ... except that you're confusing implications for holding office in the Church vs. just some generic being "Catholic").
Similarly,
cuм ex Apostolatus declares that even if a Pope (or any other church official) were accepted and recognized by all, manifest heresy would result in the loss of office.
As I said, there can be gray areas where it's not entirely clearly whether any given proposition is heretical ... and that's where someone could ahere to an opinion in good faith, even pertinaciously.
In general, the Church, in the interests of charity, gave individual a hearing before determining pertinacity. Perhaps, they though, this guy's a moron, so let's hear him out and try to figure out what he means by various propositions that sure as heck sound heretical ... since maybe he has his own definition of things. But once Luther clarified what he meant and that his meaning and sense was every bit as heretical as it sounded, it easily could have been established that he had been heretical the entire time. But, had he held office in the Church, he may not have vacated that office until it becamse known to the Church that he was in fact a heretic. That's where John of St. Thomas
quoad se vs.
quoad nos distinction comes in.