... Either way, Honorius I did not at any point during his papacy try to institute monothelism, even if he possibly did believe it. Thus, while he may have been a heretic, as Pope Alexander VI was definitely a fornicator, neither lead the Church astray.
Nonetheless the Ecumenical Council of Trullo (680 AD), which condemned him, 40 years post-mortem, called him a heretic, because of evidence available to the bishops.
Thanks for the history on Honorius I. This still seems a bit problematic for me. Let's throw out whether or not he taught it. I'm thinking it is still significant that he (may have) believed it. We all agree that the Apostles taught correctly. After Pentecost, would any of us say that any of the Apostles secretly believed in something that was error? I would not. In your faith, Pope Honorius I was a direct descendant of Apostolic succession (the biggest of his time). How could such error creep in if God is keeping everything infallible through the ages? I don't see this as being the same thing as sinning by saying an unkind word to a servant. This is much bigger.
How could any Pope be trusted if God allows this level of error? You might say that all is well because an infallible Council declared him a heretic. But that is only correct if he actually believed in the heresy. You don't seem to want to declare that as a fact, even though the Council cannot error. If every Council is only infallible based on the information available, then no Council is infallible. I thought you believed that all Councils have a special access to truth through God.
So, this leaves a big problem, it appears that the powers transferred via Apostolic succession are in fact subject to dilution through time. Pope Honorius I appeared to lack the power of discernment, which all the Apostles had in full. And if a Pope can fail here, then how are we to know anything about Popes further removed from the original Apostles? A Catholic might defend mightily something Pope Benedict XVI believes today. But how are we to know that 40 years from now a future Council won't throw it out as heresy?
The issue which has not been resolved (yet) is (1) whether Honorus' letters constituted agreement with the monothelite heresy and (2) whether they were dogmatic (i.e. ex cathedra) or merely his religious opinions.
How can these issues be unresolved? I would assume that any Council that convened to discuss declaring a POPE a heretic would have taken the issues pretty seriously. Wouldn't this be worse than impeaching a President? They couldn't have taken this lightly, knowing the damage it would do to the unity of the Church vis-a-vis the many who must have been loyal to the memory of Pope Honorius I. And yet, they felt they had enough to make the declaration they did. And, this declaration is supposedly infallible. How can there be unanswered questions of import with an infallible declaration?
FK, this is a very sticky wicket, since we Orthodox and Catholics are trying to get along these days. The traditional Orthodox understanding has always been, though, that Honorius was rightly condemned for heresy, and that this just one more high-profile example of why either a. Popes are fallible, or b. their infallibility is so narrowly defined as to make the concept meaningless, even for Catholics.
The first edition of Hefele's magisterial multi-volume Catholic history of the Councils made it clear that Honorius was found guilty of publically holding and proclaiming heresy. This was published shortly before Vatican I and the declaration of papal infallibility. Hefele was shortly thereafter forced to retract, and the entire multi-volume work was re-issued within a short time after Vatican I largely because he was forced to re-write that section.
The Catholic bishops at Vatican I who opposed the declaration of papal infallibility used this example as a prime exhibit in their case against the dogma. Little known fact: while many bishops opposed the dogma, only two had the courage to stay for the final vote and vote against it (the rest quietly left town before the vote.) One was an Italian, and the other was the bishop of Little Rock, Arkansas! I'll bet you really couldn't have gone another day without knowing that, could you? :-)
Today, the standard Catholic approach is that if a Pope's statement is incorrect, then this is evidence that he wasn't speaking "ex cathedra" in that instance.
In fairness, this isn't a lot different from Orthodox or Protestant approaches toward doctrine and dogma (when it's right, it's right, and when it isn't, then it isn't.) It is just highlighted by being focused on one man/office.
Not everything taught in an Ecumenical Council is necessarily "dogma". Only things of faith and morals. Not discipline. For example, a council teaching it is incorrect to kneel during the Mass is not an example of dogmatic, unchangeable teaching, a teaching of revelation given by Christ to the Apostles. This would be "tradition", small-"t", one that is a matter of discipline. Another example would be whether priests can marry. Orthodox allow it, Latins normally do not, although they make exceptions. Again, one asks "is this a matter of faith or morals for all time?" If yes, then we have an infallible statement - when in union with the Bishop of Rome. In Honorius I case, I don't think we have a matter of faith and morals. In any case, Honorius's problem was not faulty teachings, but not pursuing heresy sufficiently when he saw it.
Remember Peter denied Christ - yet he became the leader of the Apostolic community. What is important to remember is that God guides His Church through a special charism, a gift of the Spirit, but only regarding teaching faith and morals. It is fairly limited. Why does God allow error to "creep in"? Why does God allow sin? I think one would be hard pressed to say that the Gospel has been lost. The Church is doing its job, often times, in spite of people within the Church!
Regards