Is this actually true? How binding is the decision of Leo XIII on the validity of Anglican orders, or any later reaffirmations of that decision?
Also, there is the question of the Church’s authority in general to declare what other people believe or practice, or believed or practiced in the past. For example, when the Church condemned Nestorius at the Council of Ephesus, the heresy it attributed to Nestorius was forever bindingly forbidden for Catholics, but today some orthodox Catholics have begun to question whether Nestorius ever believed the heresy the Council attributed to him. This is even more true (except in the sense of how well known it is) of Constantinople II and its condemnation of certain long-dead people as Nestorians. Also, while I personally disagree with them, there are those who claim that Vatican II’s assertion that Muslims worship the same God as we do could be factually wrong due to a misunderstanding of Islam on the part of the Council Fathers. The Church is infallible with regard to morality and the Catholic faith, but not, I think, with regard to declaring what other people believe.
It’s my understanding that the decision that Anglican orders are invalid was based on an absence of an understanding of a sacrificial priesthood in Anglicanism for a long period of its history. Without a sacrificial priesthood, there would not be an intention to ordain a man as a true priest, and so the requirements for the sacrament of Holy Orders would not be met except perhaps for deacons, and even in that case the deacons would no longer be validly ordained once Anglican bishops were no longer validly ordained.
However, if evidence were brought forward that was not available to Leo XIII that the concept of a sacrificial priesthood did indeed survive in Anglicanism sufficiently to constitute intent to ordain a true priest, could a Catholic take the position that the Vatican decision was factually in error, though the doctrine reflected in the decision is true?
I myself have no reason to doubt Apostolicae Curae. I am speaking merely in hypotheticals.