During Vatican II's discussions on the collegiality novelty, the question arose of whether bishops get their jurisdiction from the pope (traditional teaching) or from their consecration (Modernist teaching).

Cdl. Dante wrote a letter to Paul VI during Vatican II's 3rd session:

One could make a long list of popes who were elected without being bishops and the acts of government they posed in the period between their election and their consecration. … Was the Church in error in saying that these men were Sovereign Pontiffs before their consecrations? … The [Modernist-controlled] Commission believes that it is enough to say that they had the "desire" of being consecrated. Perhaps then the will to receive a sacrament that gives a power is sufficient to receive this power? The response of the Commission is as absurd as saying that a seminarian who has the will to be ordained a priest can already validly celebrate Mass!

(source: a talk at the June 23, 2018, conference in Rome Old and New Modernism: The Roots of the Crisis of the Church)

Do sedevacantist bishops adhere to the Modernist teaching of Vatican II that the source of their episcopal jurisdiction is their episcopal consecration?

With a few exceptions (most of whom have passed away), sedevacantist bishops do not claim ordinary jurisdiction, but merely supplied jurisdiction for the Sacraments.

Why is this limited to sedevacantist bishops?  R&R bishops also lack ordinary non-supplied jurisdiction.

Interesting.  So the Church recognized as legitimate the governing acts of Pope-Elects before their episcopal consecration?  This adds even more legitimacy to the sedeprivationist position.

Yeah, I thought that was interesting, too.

Why is this limited to sedevacantist bishops?  R&R bishops also lack ordinary non-supplied jurisdiction.

Can a bishop validly consecrate new bishops during an interregnum?

from Miaskiewicz's 1940 Supplied Jurisdiction According to Canon 209:

Certainly jurisdictional power, as has been seen, is distinctly separate from the powers of Orders and therefore the power of jurisdiction does not include the faculty to bless, to consecrate, to say Mass, to anoint, or to perform some other sacred function.

So, it seems supplied jurisdiction is not needed because the power to consecrate is one of the powers of Orders.

Supplied jurisdiction allows bishops to consecrate new bishops?

Not by their own will or whim. The need must be perceived as imperative, otherwise you would have Bishops creating their own personal hierarchies. It is alway a question when you act outside of the Church's law and regulations.

During Vatican II's discussions on the collegiality novelty, the question arose of whether bishops get their jurisdiction from the pope (traditional teaching) or from their consecration (Modernist teaching).

Cdl. Dante wrote a letter to Paul VI during Vatican II's 3rd session:(source: a talk at the June 23, 2018, conference in Rome Old and New Modernism: The Roots of the Crisis of the Church)

Do sedevacantist bishops adhere to the Modernist teaching of Vatican II that the source of their episcopal jurisdiction is their episcopal consecration?

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Priests have explained to me that with supplied jurisdiction a priest gets his competency and power to forgive sins and provide sacraments to the faithful in cases of necessity, and that they get this jurisdiction supplied by the Church acting through their ordination. We distinguish but we do not separate. Their ordination is important, and it is distinguished from the power of the Church to supply jurisdiction, but these are not to be separated, such that we leave out the Church and only focus on their ordination. It is the Church acting THROUGH the priest's ordination which we speak of when we say, "supplied jurisdiction."
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Since episcopal consecration is not a separate sacrament but rather the perfection or "fullness" of priestly ordination (we distinguish but we do not separate), it would seem the same principle applies to bishops, that in cases of necessity they have the power to consecrate more bishops without papal mandate, when the power of the Church supplies jurisdiction and that acts through the bishop's consecration. This is the case with the 4 SSPX bishops in the same way also with the 3 new bishops under +Williamson's episcopacy, all of which occurred under a state of necessity, so the Church supplied the necessary jurisdiction acting through the consecration of ABL and +AdCM, and so on: things like that.
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ABL suffered much anguish over his decision to do that in 1988, and was supported by +Antonio de Castro Mayer when they both laid hands on each of the 4. So too when +W consecrated Fr. Faure (who had been ABL's first choice from the beginning!), then later both +W and +Faure together consecrated Fr. Thomas Aquino, and then again when all three consecrated Fr. Zendejas. None had a papal mandate but in all 7 cases it was judged by the consecrating bishops that a sufficient case of necessity existed.
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It's most telling that when Pope Benedict XVI so-called lifted the excoms on the 4 surviving bishops, no mention was made of that applying to ABL and/or +Mayer posthumously. One could argue the excoms were invalid all along, and the proper thing to do would have been annulment, but that would have implied the deceased two were never excom'ed as well. So Newchurch did the "Romanita" thing, which amounts to an act of cowardice. They have allowed ABL and +AdCM to wear their so-called excommunication as a badge of honor!
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Notice that Newrome has taken no action on the three new +W bishops. That would be "stepping in it."
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I have heard CMRI priests say they receive their priesthood from the imposition of the bishop's hands.
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Another knowledgeable priest explained to me that "One cannot give that which he does not have," in context of a priest being able to ordain another priest (because he in fact has that degree of the priesthood), and that a priest can confer confirmation since he has been confirmed himself, and he is a priest, so confirmation is something that he "has." This would be in a situation of necessity such as when a bishop is not available and a great and urgent need exists for confirmation. In such a case the priest might need to obtain approval of a bishop to provide confirmation without the bishop's personal real presence, but I'm not clear on that. It would seem all the more appropriate for him in order to ordain a priest (having to obtain permission from a bishop). However, since a priest has not been raised to the highest order of the priesthood and does not "have" episcopal consecration, it would mean that the priest cannot consecrate another priest a bishop, because that's something he "doesn't have." But I'm not absolutely sure how the fine points pan out.
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These are all cases of the Church supplying jurisdiction (even without Papal mandate) for the priest to provide valid sacraments.
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Therefore, while the imposition of hands are part of the sacraments (confirmation and priestly ordination) and therefore cannot be SEPARATED (by saying that's where the validity comes from), it must be DISTINGUISHED (imposition of hands is not one and the same thing as jurisdiction or providing the sacraments). We distinguish but we do not separate. 
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This overshadowing principle applies to many things in the Church. We distinguish the Mass from the consecration of the host, but we do not separate them, therefore, the eucharistic consecration happens in the context of the Mass but is not a "separate" act, rather it is a distinguished act (the Offertory is not the Consecration). The Consecration is not removed from the Mass (not separated). And so on. As Fr. Schell used to say so often, "Things like that."
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Can a bishop validly consecrate new bishops during an interregnum?

from Miaskiewicz's 1940 Supplied Jurisdiction According to Canon 209:
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Quote from: p. 12

Quote

Certainly jurisdictional power, as has been seen, is distinctly separate from the powers of Orders and therefore the power of jurisdiction does not include the faculty to bless, to consecrate, to say Mass, to anoint, or to perform some other sacred function.

So, it seems supplied jurisdiction is not needed because the power to consecrate is one of the powers of Orders.

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The guiding principle is, "We distinguish but we do not separate." The words, "distinctly separate," do not follow this principle.
For example, this quote from Miaskiewicz implies you can have jurisdictional power without Orders as well as Orders without jurisdictional power. This introduces confusion instead of clarity!
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Therefore, it would seem this quote from Miaskiewicz contains a mistake. Where it has "distinctly separate" it ought to have "distinguished." If those words are replaced, it would say:
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Certainly jurisdictional power, as has been seen, is distinctly separate (distinguished) from the powers of Orders and therefore the power of jurisdiction does not (inherently and necessarily) include the faculty to bless, to consecrate, to say Mass, to anoint, or to perform some other sacred function.
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But this quote introduces another principle, namely that of "faculty," so I suggest the addition also of "inherently and necessarily."
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A priest gets his faculties from his legitimate superior(s).
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Perhaps someone else can comment on priestly faculties.
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As for me, I can say this much:
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I have heard that in modern colleges the longstanding principle of human faculties (sight, discernment, physical prowess, dexterity, speech, writing, flying helicopters, commanding an army, etc.) became such a problem for modern philosophers, that they eventually took up the denial of faculties per se. This means that whenever the topic came up they would say, "There are no faculties."
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They could not cope with the logical consequences of human faculties, so they resorted to denying they exist!
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I would say this is an example of how far off the rails of RIGHT THINKING that modern philosophy takes its adherents!!
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I am only aware of two instances where individuals were given the authority to consecrate bishops without papal mandate - Monseigneur Pierre Martin Ngo Dinh Thuc, titular bishop of Saigon ( 15 March, 1938 ) and Monseigneur Michel d'Herbigny, S.J., titular bishop of Trcie ( 10 March, 1926 ).

Can you provide more details on that?