"Interviewer: In the case of heresy, just as a heretical Christian ceases to be a member of the Church, does the pope also cease to be pope and head of the ecclesial body, and lose all jurisdiction? Mgr. Bux: Yes, heresy undermines faith and membership in the Church, which are the root and foundation of jurisdiction. This is the thinking of the Church Fathers, especially of Cyprian, who had to deal with Novatian, antipope during the pontificate of Pope Cornelius (cf. “'Lib. 4, ep. 2”'). Every believer, including the pope, separates himself from the unity of the Church through heresy. It is well known that the pope is at the same time a member and part of the Church, because the hierarchy is within and not above the Church, as stated in Lumen Gentium (n. 18)."