[sitetest]

The pope would remain a bishop, but if a heretic, would nonetheless lose communion with the Catholic Church and cease to be pope.

But only the College of Cardinals could pronounce him formally a heretic, or a successor pope.

At best, we laymen can note that a pope seems to be in heresy, but we have no authority to actively act on that conclusion.

[Domestic Church]

What about sensus fidei? At some point, that would kick into gear so to speak.

[Mrs. Don-o]

I have heard it asserted that the College of Cardinals can depose a pope, and I have heard it asserted that they could not, the reason being: only an Ecumenical Council could depose a pope, and then only for heresy: but no gathering of bishops and/or cardinals is an Ecumenical Council unless the rightful pope assents to its proceedings.

I understand that the way out of this Catch-22 only exists when there are more than one claimants to the papacy: therefore the Council could "depose" the anti-pope (the false pretender), but only with the assent of the true pope.

Or, both the anti-pope and the true pope could resign, and then the Council would be free to have a conclave to elect a new pope. Isn't this what happened at the end of the Great Western Schism (15th century)?

Catholic Encyclopedia, last two paragraphs (LINK)

I admit this isn't all quite clear, but this is my impression. Any corrections welcome.