So ... yeah, we know that the final determination requires authority, but we can make arguments and establish some significant positive doubt.

But then you contradict yourself.  IF these guys have been Popes, they have in fact already determined with papal authority that these Rites are valid.  So the case is closed.  That is in fact the single strongest argument in favor of the validity of the Rites, even if it rests on the disputed premise of their legitimacy ... but most R&R will not go there,

because they've spent decades arguing against the Church's disciplinary infallibility,

since that same infallibility, which would ensure the validity of the Rites, would also ensure that the Church..."

"...because they've spent decades arguing against the Church's disciplinary infallibility,..."

SSPX= R&R, so I don't think we are talking about the same Church... +L preached mostly about the infallibility of Eternal Rome, the Church of Tradition, the TRUE Church.  Can you give examples that they were arguing against the Church's disciplinary infallibility?  They would criticize N.O. church ( in the real SSPX) . I not  2 % theologian.
Laymen can doubt sacraments, and they should rebuke bishops  'to their face' if something isn't done correctly. +L even considered N.O. baptisms to be valid,

["... je ne dis pas que tous les sacrements soient invalides, ni qu’ils soient hérétiques, mais ils sont empoisonnés : ils ont une autre orientation, ] 1976, Associations St Pie V, 
{...I don't say that all the sacraments are invalid, neither that they are heretical, but that they are poisoned,: they have an other orientation..."

because so many things were deleted in the N.O. rite. But at other times he would simply say: "This is not my problem, it is God's problem". or something very close to that. This is the reason for Conditional sacraments, no?

I actually don't really believe in the Church's disciplinary infallibility. Despite being the common opinion of theologians, it remains an opinion. I find it interesting that when the Church defined infallibility, She only bothered to do so regarding Her solemn magisterium. Why not just tell us clearly that Her universal laws and rites are also dogmatically impeccable? She didn't bother and it wouldn't have been that hard. Makes me wonder. Even about the Universal, Ordinary Magisterium.

Even if it hasn't been defined, that's objectively heretical and will be condemned as such when this all blows over.  So, according to you, the Church can fail in her mission of saving souls by, oh, promulgating a Mass that offends God and brings harm to souls, or establish a cult for "saints" who are likely in Hell and at the very least were enemies of the Faith.  It's terrifying to see how many of you are losing the faith.  That's to say nothing about how idiotic it is to assert that because Vatican I had not defined it ... yet ... that it isn't true.

Dogmatically impeccable?  That's not a thing.

As for why not define it ... well, Vatican I was interrupted by various wars the Masons started to interrupt it.  So they may have gone on to define it.  But even if they chose not to, that could be fur any number of reasons.  Even with what they did define, there were many inopportunists who didn't think it should be defined, even while believing it to be true.

God permitted them not to define it to be a test of faith today ... one that you are failing.

VI. THE FORENSIC VERDICT: SUMMARY OF FINDINGS

Based on the evidence gathered through this audit, the following findings are established regarding the 1968 Rite of Ordination (Pontificalis Romani):

1. The Failure of Signification (The "Ask/Receive" Defect)

- A Sacrament is an efficient sign that must explicitly point to the specific supernatural reality it intends to create.

- The 1968 Rite surgically removed the specific petition for the power to offer the Propitiatory Sacrifice (Hostias Salutares).

- By substituting this with a generic request for "meritorious ministry," the rite fails to "Ask" for the Priestly Character.

Finding: Where there is no specific "Ask" for the Power, there is no specific "Receive" of the Character.


2. The Juridical Substitution (Valorem vs. Validitatem)

- The Curial architects utilized a semantic shift from validitatem(ontological being) to valorem (legal rank).

- The 1968 decree defines the "essential words" as pertaining to the "nature of the thing" (naturam rei) and required only so that the "act may have value" (ut actus valeat).

Finding: The rite is designed to install a man into a legal "Nature" (Rank) within an administrative structure, but it lacks the language required for ontological "Validity" in the Order of Being.


3. The Severing of the Apostolic Lineage

- In the Traditional Rite, the "Transfusion" clause (Petition A) identifies the transmission of the "Mystical Blood" (Power) from the Bishop to the Priest for the purpose of offering Sacrifice.

- The 1968 Rite retains the verb transfudisti but directs the transfusion toward a "meritorious ministry," which is a redundancy of Grace, not an identification of Power.

Finding: By removing the "trace" of the Sacrifice from the very clause intended to transmit the Priesthood, the Apostolic Succession is effectively severed.


4. The Irrelevance of Ministerial Intent

- The Church is the servant, not the master, of the Sacramental signs.

- The intention of the minister is "borrowed" from the rite; a minister cannot intend to effect a power that the rite itself has deliberately excluded.

Finding: Because the form is "broken" in its signification, the personal intent of the ordaining bishop is incapable of repairing the ontological nullity of the act.

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FINAL JUDGMENT

The 1968 Rite represents a substantial departure from the "Ontological Law" of the Magisterium. It replicates the Anglican defect condemned by Pope Leo XIII by surgically removing the mention of the Sacrifice and the Sacerdotium from the operative prayers.

Consequently, it is the conclusion of this audit that the 1968 "Presbyter" possesses the Valorem (Legal Status/Rank) granted by an administrative structure, but possesses nulla Validitatem (Zero Validity) in the Order of Being. The rite fails to communicate the Sacramental Character, leaving behind a legal shell that has the name of a Church but has lost the means to effect the Priesthood of Jesus Christ.