Mike: Is it licit for me to attend a sedevacantist church in my area? There is no reverent Mass that I can go to.
Bishop Athanasius Schneider: No, it is never permitted to attend in this case, because this is a true schismatic community, somewhat comparable to the Orthodox churches. There is a difference with the Society of Saint Pius X. The Society of Saint Pius X accepts the Pope; they name him in the Mass, and they pray for him, so there are Catholics in this way. The problem is that they do not obey him in concrete orders that the Pope has given. But this is only a canonical, exterior aspect of obedience, which in the extraordinary crisis of the Church somewhat justifies the situation of the Society of Saint Pius X. The crisis is so enormous, and the Popes have in some ways allowed or promoted some bad things in the Church, in the liturgy and elsewhere, which explains the situation of the Society of Saint Pius X as temporary.
What is important is to believe in the primacy of the Pope. It is not always necessary for the fullness of Catholic truth to obey every singular order of a Pope, but we must obey when he commands in accordance with the true doctrine of Christ. In this case, the Society of Saint Pius X obeys the true doctrine the Church has always had, even if concrete canonical submission is difficult in our time. This is the difference between the situation of the Society of Saint Pius X and sedevacantist communities.