So firstly let me make very clear - I am not insinuating that any Pope past or present is a heretic or holds heretical beliefs.
However, I’m obviously reflecting on this question due to the current controversy over what Pope Francis did or didn’t say about civil unions. I’m going to choose to hope that it was a misinterpretation or misquote until further evidence arises.
Anyway, my question: Has there ever been, in the past, a Pope who was a public heretic (obviously if someone held heretical beliefs privately we’d never know), and what happened to them as a result? Is there a canonical process for such a situation?
If a Pope in the future were to say they believed something that was fundamentally opposed to Church teaching, for example, that they believed women should be ordained or that the devil didn’t exist, how would that affect their position as Pope?
Obviously I know that regardless of a Pope’s own opinion or beliefs Church teaching is protected by the Holy Spirit from alteration. I know the gates of Hell shall not prevail. Just curious about this hypothetical.