Ah, yes, the refuge of juridicalism.
So, let's see . . . He "actively maintained the heresy in official papal letters written to Sergius I, patriarch of Constantinople in reply to a formal consultation and to several other individuals"--but this was not in a doctrinal statement.
Well, an Ecumenical Council determined Honorius was a heretic. In fact, another Pope, Leo II, in adding his approval to III Constantinople also condemned Honorius, stating "he 'endeavoured by profane treason to overthrow the immaculate faith of the Roman Church', not because of mere negligence (as some also lie)."
Further: "Two succeeding ecumenical councils ratified the sentence, Council II Nicea (787) and IV Constantinople (869-70). Popes approved both. From the eighth to the eleventh century all new popes had to swear in their Papal Oath before assuming the office that they accepted that III Constantinople had authoritatively anathematised Honorius. This is found in the Liber Pontificalis and in the Liber Diurnus."
So, um, yeah, apparently THREE Ecumenical Councils didn't think the "his heretical statement was not in a doctrinal statement" a good enough defense.
You need a more comprehensive reading of the events:
The Pope, with no idea of Sergius' between-the-lines message, answered the Patriarch on the unthinkable subject of Christ's "opposition" to the Father. "We confess one will of our Lord Jesus Christ, since our (human) nature was plainly assumed by the Godhead, and this being faultless, as it was before the Fall." [Quoted in Charles Joseph Hefele, A History of the Councils of the Church, vol. 5 (Edinburgh: T. & T. Clark, 1896; AMS Reprint, 1972), 29]. Since Christ's human will is "faultless," there can be no talk of opposing wills. (Christ hardly would have been faultless if he opposed his Father's will.)
Monothelites, as they grew in numbers and influence over the ensuing years, seized upon Honorius' confession of "one will of our Lord Jesus Christ" as confirmation that the Pope believed with them that Christ had no human will. Newman and other commentators have noted that Honorius' letters to Sergius are not doctrinal definitions ex cathedra; thus they are outside the scope of infallibility defined by the First Vatican Council.
That is true, but, even more to the point, a look at Honorius' exact words shows that while he did use a formula--"one will"--that was later declared heretical, he used it in a sense that implied the orthodox belief.
This was picked up as early as 640 by Pope John IV, Honorius' successor, who pointed out that Sergius had asked only about the presence of two opposing wills. Honorius had answered accordingly, speaking, says Pope John, "only of the human and not also of the divine nature." Pope John was right. Honorius assumed the existence of a human will in Christ by saying that his nature is like humanity's before the Fall. No one would claim that before the Fall Adam had no will. Thus Honorius's speaking of Christ's assumption of a "faultless" human nature shows that he really did believe in the orthodox formula of two wills in Christ: one divine, one human, in perfect agreement.
The Third Council of Constantinople was thus in error when it condemned Honorius for heresy. But a Council, of course, has no authority except insofar as its decrees are confirmed by the pope. The reigning Pontiff, Leo II, did not agree to the condemnation of his predecessor for heresy; he said Honorius should be condemned because "he permitted the immaculate faith to be subverted." [Carroll, 254]
This is a crucial distinction. Honorius probably should have known the implications of using the "one will" formula; he could have found out by writing a letter to Sophronius of Jerusalem. But he was no heretic.
The anti-papists got the wrong guy. It seems incredible that so many readers of Honorius's letters, from Patriarch Sergius to Hans Kng, see only what they want to see in Honorius's "one will" formula. We should thank God that this poor old pope saw fit to explain himself. Rarely outside of the homoousios/homoiousios controversy at the First Council of Nicaea has so much hinged on so few words.
Since this case seemed to be the best one the anti-infallibilists could turn to, I became an infallibilist, a Catholic with faith in the pope as the Vicar of Christ and successor of St. Peter. The Church will live beyond the trials of these days as it did those of Honorius's day. That bare fact may seem abstract and impenetrable in the convulsions of our age, yet it is our unshakable guarantee.http://www.catholic.com/thisrock/1994/9409fea2.asp