Can a Council Judge a Case of Papal Heresy?
S. B. Smith provides a possible answer: There are two opinions: one holds that he is by virtue of divine appointment, divested ipso facto, of the Pontificate; the other, that he is, jure divino, only removable. Both opinions agree that he must at least be declared guilty of heresy by the church-i.e., by an ecumenical council or the College of Cardinals.
Let us analyze whether it is possible for a Council to judge a case of alleged Papal Heresy.
There can be no Ecumenical Council unless it is convoked by the Roman Pontiff. ... There are two propositions in the case of alleged papal heresy. The first is that the Pope resigns by the act of heresy as does any other cleric. (See Canon 188, paragraph 4) The second is that someone must declare the Pope a heretic, which will then effect his deposition.
In the first case, the Pope has laready resigned by an act of heresy, therefore the Papacy is vacant.
Since the Papacy is vacant, there is no one who can summon a General Council, therefore in this case a General Council is unable to declare the Papacy vacant, because it cannot be called into session.
In the second case, the General Council must declare the Pope a heretic. So we must reason that the heretical Pope must call the Council, so it can declare him a heretic and the Papacy vacant.
If the Roman Pontiff should die during the celebration of the Council, the Council is by law automatically suspended until the new Pontiff shall have ordered its resumption. (Canon 229) In the first case, the Pope has resigned, which is equivalent to death, which suspends a sitting Council, so it cannot proceed. In the second case, the Council could theoretically proceed, since it is already convened, but the moment it issued its declaration it would be supended, turning the matter over to the Cardinals to elect a new Pope.
Basically both propositions are in practice unworkable, so we must conclude that a General Council cannot judge a case of alleged Papal heresy.