Those who accuse Popes of grave errors and grave failings of faith — the papal accusers — often claim that an “imperfect” Ecumenical Council can depose the Pope. Such a Council is not truly Ecumenical, as it exists in opposition to the Roman Pontiff. (Hence the term “imperfect”.) A true Ecumenical Council is the body of Bishops gathered with the visible head of the Church, the Pope. A body without a head is a monster, not an Ecumenical Council “gathered in the Holy Spirit”.

Then the Magisterium clearly teaches that the body of Bishops, even altogether, has no authority in opposition to the Pope. Therefore, so far from judging and deposing the Pope, they cannot even declare that the Pope is a “manifest heretics” and that he ceases to be the Pope by the judgment of God, as some papal accusers claim. Instead, the Pope can never be a heretic, nor teach heresy.

Pope Leo XIII in Satis Cognitum 15:
“This power over the Episcopal College to which we refer, and which is clearly set forth in Holy Writ, has ever been acknowledged and attested by the Church, as is clear from the teaching of General Councils. ‘We read that the Roman Pontiff has pronounced judgments on the prelates of all the churches; we do not read that anybody has pronounced sentence on him’ (Hadrianus ii., in Allocutione iii., ad Synodum Romanum an. 869, Cf. Actionem vii., Conc. Constantinopolitani iv) [Pope Adrian II, in Allocutions 3, to the Synod of Rome, year 869; compare Acts 7, Fourth Council of Constantinople]. The reason for which is stated thus: ‘there is no authority greater than that of the Apostolic See’ (Nicholaus in Epist. lxxxvi. ad Michael. Imperat.) [Pope Saint Nicholas I in Letters 86 to emperor Michael] wherefore [Pope Saint] Gelasius on the decrees of Councils says: ‘That which the First See has not approved of cannot stand; but what it has thought well to decree has been received by the whole Church’ (Epist. xxvi., ad Episcopos Dardaniae, n. 5) [Letters 26, to the Bishops of Dardania].”

“It has ever been unquestionably the office of the Roman Pontiffs to ratify or to reject the decrees of Councils. [Pope Saint] Leo the great [I] rescinded the acts of the Conciliabulum of Ephesus [the so-called robber council of Ephesus in 449; not the Ecumenical Council of Ephesus in 431]. [Pope Saint] Damasus [I] rejected those of Rimini [Council of Ariminum], and [Pope] Adrian I, those of Constantinople [Council of Constantinople (692), also called Trullo or Quinisext Council; Council of Constantinople (754), also called the Council of Hieria]. The 28th Canon of the Council of Chalcedon, by the very fact that it lacks the assent and approval of the Apostolic See, is admitted by all to be worthless. Rightly, therefore, has Leo X laid down in the 5th council of Lateran ‘that the Roman Pontiff alone, as having authority over all Councils, has full jurisdiction and power to summon, to transfer, to dissolve Councils, as is clear, not only from the testimony of Holy Writ, from the teaching of the Fathers and of the Roman Pontiffs, and from the decrees of the sacred canons, but from the teaching of the very Councils themselves.’ Indeed, Holy Writ attests that the keys of the Kingdom of Heaven were given to Peter alone, and that the power of binding and loosening was granted to the Apostles and to Peter; but there is nothing to show that the Apostles received supreme power without Peter, and against Peter. Such power they certainly did not receive from Jesus Christ. Wherefore, in the decree of the Vatican Council as to the nature and authority of the primacy of the Roman Pontiff, no newly conceived opinion is set forth, but the venerable and constant belief of every age (Sess. iv., cap. 3) [Pastor Aeternus, chapter 3].”