Let the Resistance summarize in two or three simple theological propositions the Truths they claim that Rome needs to accept that it does not accept. Can it do this? Everything the Resistance claims to believe, the Society also believes and defends. The Kingship of Christ, the immutability of dogma, that Holy Mass is a Propitiatory Sacrifice, or anything else that may be denied in the modern Church. But the difference is that the Society knows that there is no precedent in Tradition itself, nor even in Archbishop Lefebvre's thoughts and words over a long period of time, for completely cutting off all contact with the Roman Authorities. In the meanwhile, the SSPX continues its work. If the path for doctrinal discussions opens up again, the Society will take it. It's a good opportunity to influence mainstream Churchmen with the full Gospel of Christ and His Church.
"Here is why I have always thought that I had to go to Rome, that I had to write, that I had to visit these cardinals in order that they should not say that we are doing nothing or that we no longer recognize them or that we wish to have no contact with them. They cannot say that I have not done everything in my power to try to stay in contact with them. However, I think what counts much more are the facts, than the words or writings, even for Rome. What are the facts which count for us? The seminaries! To make priests! To make traditional priests, priests according to Tradition, to make good and holy priests in our seminaries. That is the work we must carry on with and the work which counts in Rome."
https://www.sspxasia.com/Docuмents/Archbishop-Lefebvre/Conference_at_Long_Island.htm