I thought the Vatican's stance on the issue was that the SSPX priests were licit but their duties were "suspended".
As long as there are no changes which may lead to the re-establishment of this necessary communion, the whole Lefebvrian movement is to be held schismatic, in view of the existence of a formal declaration by the Supreme Authority on this matter ... As the Motu Proprio declares in no. 5 c) the excommunication latae sententiae for schism regards those who "adhere formally" to the said schismatic movement. Even if the question of the exact import of the notion of "formal adherence to the schism" would be a matter for the Congregation for the Doctrine of the Faith, it seems to this pontifical Council that such formal adherence would have to imply two complementary elements: ... In the case of the Lefebvrian deacons and priests there seems no doubt that their ministerial activity in the ambit of the schismatic movement is a more than evident sign of the fact that the two requirements mentioned above (n.5) are met, and thus that there is a formal adherence. (Pontifical Council for the Interpretation of Legislative Texts, Annex to Prot.N. 5233/96)
I don't know exactly what the legal standing of the Priests are. That is being argued back and forth, but I suspect one side is on firmer footing than the other.
I am of the belief that attending an SSPX Mass satisfies ones Sunday obligation, but the reception of Communion, or any other Sacrament, is not recognized.
Furthermore, exclusive attachment to SSPX is grounds for excommunication without notice (in sententiae).
The indult Mass I attend though is probably due in most part to the actions of the SSPX. Without them there would be no incentive for the Bishops to grant the indult. So possibly they do play a part in Jesus' master plan. But you know what they say about commiting a sin to achieve a good.
But since my Church is right across the street from an SSPX Chapel, I am convinced that people cross the street for Confession and Communion on some kind of regular basis. I hope that the avowed SSPX'rs of FR do the same thing. I think that would satisfy every requirement.
All SSPX Sacraments are valid but technically illicit due to the Society's irregular situation with Rome. Yet this same Vatican gives permission to attend SSPX Masses. As noted above, even an archbishop in the curia identifies the SSPX as a remnant and defender of the Catholic Faith.
Sacraments such as Penance and Marriage which require jurisdiction are covered under supplied jurisdiction in Canon Law (explanation below)
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Jurisdiction is ordinarily given by mandate from the Pope or diocesan Bishop, or perhaps delegated by the parish priest. The priests of the Society of Saint Pius X do not have jurisdiction in this way. Extraordinarily, however, the Church supplies jurisdiction without passing by the constituted authorities. This is foreseen in the 1983 Code of Canon Law:
· when the faithful think the priest has a jurisdiction which he does not have (canon 144) [common error]
· when there is a probable and positive doubt that the priest has jurisdiction (canon 144)
· when a priest inadvertently continues to hear confessions once his faculties have expired (canon 142, 2)
· when the penitent is in danger of death (and then even if the priest is laicised or an apostate, even though a Catholic priest is at hand) (canons 976, 1335).
Therefore, the Church, wanting the ready availability of penance, extraordinarily supplies jurisdiction in view of the needs of her children, and it is granted all the more liberally the greater their need.
Now the nature of the present crisis in the Church is such that the faithful can on good grounds feel it a moral impossibility to approach priests having ordinary jurisdiction. And so, whenever the faithful, need the graces of penance and want to receive them from priests whose judgment and advice they can trust, they can do so, even if the priests do not ordinarily have jurisdiction. Even a suspended priest can do this for the faithful who ask: “for any just cause whatsoever” (canon 1335). This is even more the case if a faithful Catholic can foresee his being deprived of the true sacrament of penance from priest with ordinary jurisdiction until he dies.
The extraordinary form for marriages is foreseen in canon 116,1. If the couple cannot approach their parish priest “without serious inconvenience” – and they may consider as such his insistence on having the Novus Ordo Missae for the wedding, or their apprehensions concerning his moral teaching in marriage instructions – and if they foresee these circumstances to last for at least a month, then they can marry before witnesses alone, and another priest (e.g., Society of Saint Pius X) if possible (canon 1116,2).
Even if one were to consider the above arguments as only probable, then jurisdiction would still be certainly supplied by the Church (canon 144). And so we must answer affirmatively. Traditional priests do have a jurisdiction that is neither territorial nor personal but supplied in view of the needs of the faithful.”
---Most Asked Questions about the Society of Saint Pius X.