I see no one has the courage to respond to my challenge.  It’s not a trap.  I don’t have or know of any gotchas that I can throw at you if you say it is a defection.  I would just like to know on what basis you would say it is so.  The whole purpose of this type of ecclesiology is to establish the apostolic origins of the hierarchy.  So why do you think a sede vacante cuts the connection back to the Apostles?  Please explain.

Just passing through for now. Any sources if need be later on. Btw, I didn't downthumb your post, Clemens. Just to clarify something: as you know, I often abbreviate with convenient acronyms (e.g. Ecclesia-Vacantism as EVism) something I don't feel like typing out in full every time, and which comes up often. So, that's why I abbreviated Sixty One Year SVism. I realized it would soon become Sixty Two Year SVism or STY-SVism in just another 5 odd days. Hope that clears it up.

Now, where were we? Ok, your question:

Right, we shouldn't try to trap each other, and I hope and think I'm not doing either; but just try to help each other. As one of my former sede friends liked to say, "we are like students in a theology class notes sharing notes". That's all.

Why do I think the sede-vacante cuts the connection back to the Apostles? Because, I believe the Apostolic Mission can only be transmitted by the Successors of Peter. Hence, there must be Perpetual Successors to St. Peter, or the Apostolic Mission will be lost.

Syllogism:

Major: The Apostolic Mission of the Church can only be transmitted by the Successor of Peter.
Minor: But the Apostolic Mission of the Church cannot be lost.
ConC: Therefore, there must be Perpetual Successors to St. Peter until the end of time.
Corol: Therefore, in my perspective, an indefinite SVism (e.g. 150+ year) is not possible.

So, now, from my side, again serious question. Not intending to trap anyone, but just in the interest of learning and "sharing notes" together: suppose some Old Catholic, or relatively extreme sedevacantist, claimed Pope Pius IX was either not validly elected Pope or fell into heresy at Vatican I, and all subsequently elected Popes have been heretics, and thus we have had no Successors to St. Peter.

What do you think would be the best way to answer that opinion, which is clearly and manifestly erroneous? Imho, the best way to proceed would be something like the above; showing that an interregnum lasting that long is simply not possible and precluded by Catholic Faith. How would you proceed to refute that error?

God Bless.

If the Old Catholic bishops were right, apostolic succession would continue through their consecrations of other bishops in a state of emergency/necessity.

If they were wrong, the succession would continue in Pius XII and his successors.

Either way, the succession would continue.

What "emergency"?You have a living, reigning pope continuing to appoint successors to the Apostles.

What are your thoughts on the Successor of Peter being necessary to transmit Apostolic Mission? Can the Apostolic Mission be lost? Imho, God has shown us clearly, by allowing that last Archbishop Emeritus Bernardino alive, to be appointed only in 1960 under Pope John XXIII, that it is not possible that Pope Pius XII was the last Pope; otherwise the Apostolic Mission would be lost.

That's his opinion, but it is not shared by others.  Your assertion that the rejection of this opinion is heretical grossly overstates the theological note of that conclusion.  You really need to be careful.  In denouncing people as heretics for differences of opinion that are not in fact heretical, you run the risk of developing a schismatic attitude (my chief complaint about the Dimonds and some other dogmatic sedevacantist types).  Theologians posited scenarios in which all the Curia, Cardinalate, etc. were wiped out in a disaster or war of some kind.  They did not consider it to have any serious implications regarding the defectibility of the Church, and held that the Church could otherwise still elect a Pope.  Time is not relevant to the scenario.  We could hypothetically see the entire Curia and Roman clergy wiped out in a nuclear attack, for instance.  If God would allow that to happen, the Church would not defect ... as the remaining bishops in the world could designated a successor to St. Peter.

On the other side, I agree with you that the Magisterium and Universal Discipline of the Church can never got off the rails in any substantial way.  Only difference is that, unlike pretty much everyone on this forum except for poche, you insist that there is in fact no substantial error in V2 or the NOM.  To me, it is beyond obvious that there is, and the conclusion is further confirmed by the pernicious fruits of these things.  Consequently, I must conclude that the See of Peter is most likely vacant.  Or, alternatively, something else is going on where the Catholics Popes have not been acting freely in promulgating these errors.