Can heretics excommunicate? Foundational canonical text says they cannot
SSPX defenders would do well to read this explanation of the discussion in Gratian's Decretum. It's good news – if they're prepared to do what is necessary...

SSPX defenders would do well to read this explanation of the discussion in Gratian’s Decretum. It’s good news – if they’re prepared to do what is necessary...
Editor’s Notes
If Leo XIV excommunicates the SSPX following 1st July’s episcopal consecrations – and extends this excommunication to the priests and the faithful – what will this mean?
And what arguments might be cogent?
Around 1140 AD, an Italian monk named Gratian collected and ordered the great mass of canonical legislation which had built up over the centuries before. Prior to the codification of Canon Law in 1917, the Church’s law was considerably less neat and tidy – but Gratian’s work marked the beginning of a new period of order.
This work came to be known as Gratian’s Decree, or Decretum. In some ways similar to Denzinger’s work, Gratian’s Decretum was not an official work, but – as Bouscaren et al. put it – “it was so useful that it soon became the best-known book of canon law.” After Gratian’s death, it was supplemented with other collections, such as the Decretals of Gregory IX, and collections by Boniface VIII, John XXII and others.
The Decretum is far from being solely a book of legislation. It contains many theological texts from magisterial and patristic texts, as well as Gratian’s comments. Its influence is clear, when we consider that these theological texts are cited by theologians, with the references customarily assigned to them in the Decretum.
As already mentioned, the texts cited in the Decretum have their own intrinsic and theological authority, given that they are derived from Popes, saints and fathers. As such, the codification of Canon Law in 1917 – which abrogated various laws which it did not expressly contain – does not touch the theological reasoning and authority of various points cited in the Decretum, or the Decretum’s own witness to the tradition of the Church.
Causa XXIV is no exception. Doctor of the Church St Robert Bellarmine, as well as Cardinal Juan de Turrcremata OP and others, refer to this section of the Decretum, and in particular its canon Audivimus.
This canon, and the discussion as a whole, deals with the question of whether heretics can validly excommunicate non-Catholics.
However, recourse to this canon and the theological principles behind it comes at a cost.
The SSPX episcopal consecrations
As stated, this is a very relevant issue, given the imminent episcopal consecrations of the Society of St Pius X.
It is very likely that Leo XIV’s Vatican will declare that the new bishops, and their consecrators, have automatically excommunicated themselves; it is also possible that his Vatican will attempt to excommunicate the priests and other members of the SSPX; finally, it is also rumoured that this will be extended to anyone who attends Mass at SSPX chapels.
These “active” or “positive” inflictions of excommunication (e.g. in “condemnatory sentences”) appear to pose a different problem to the latae sententiae exommunications, or “declaratory sentences” of such.
In 1988, John Paul II’s Vatican declared that these excommunications had taken place, and the SSPX provided arguments denying this; a different line of argument would be necessary in the face of a positive infliction of excommunication.
To understand why, and the nature of the problem this would post, let us consider the following magisterial condemnations.
Unjust excommunications should be feared
Historically, some associated with the SSPX have given the impression that an unjust excommunication is null and void, and can be ignored.
Before publishing this article, the canon lawyer Mr Marc Balestrieri (who also assisted with finding the best edition of Gratian) drew my attention to the following by the sixteenth century Dominican Bartolomeo Fumo:
“Excommunication, even if it be unjust – so long as it is not null, and even if it ought to be annulled – is to be feared, according to Petrus] de Paludanus (4. sent., dist. 18. q. 1. art. 3). [This is so] whether it be unjust on the part of the excommunicated person, who is innocent, or on the part of the one excommunicating, who does not issue it from zeal for justice but from hatred or some other bad motive, or on the part of the procedure, because it proceeded by false witnesses, or without a warning, or the like.
“And he who should despise it would sin mortally on account of disobedience to the Church and would incur the penalties of the law; and then it is just. Absolution is therefore to be sought, and [the excommunication] is to be observed.
“But if it is entirely null, and by not observing it no scandal follows, it is neither to be feared nor to be observed. If, however, by not observing it scandal follows for others, it is to be observed on account of the scandal. But if it is unjust but secret, see what is said under the actual effect of excommunication.”1
This position is confirmed by the magisterium of the Church. Consider the following proposition of the English heretic John Wycliffe, condemned in the letter Super periculosis of 1377:
“A curse or excommunication does not bind absolutely except when it is given against an opponent of the law of Christ.” (DH 1131)
The same document condemned the following:
“Excommunication by the pope or by any prelate is not to be feared, because it is the censure of the Antichrist.” (DH 1180)
Wycliffe, like many Protestants, believed the papacy to be an Antichrist institution. Notwithstanding certain comments made by Lefebvre about recent claimants being “antichrists”, this is clearly not what the SSPX believe.
However, Pope Clement XI condemned the following propositions of the Janesnists in the Bull Unigenitus:
91. The fear of an unjust excommunication should never hinder us from fulfilling our duty; never are we separated from the Church, even when by the wickedness of men we seem to be expelled from her, as long we are attached to God, to Jesus Christ, and to the Church herself by charity. —Jn 9:22-23.
92. To suffer in peace an excommunication and an unjust anathema rather than betray truth is to imitate St. Paul; it is far from rebelling against authority or destroying unity. —Rom 9:3 (DH nn. 2491–2)
The global censure given the various condemned propositions is as follows:
“We declare, condemn, and reject ... the preceding propositions, as the case may be, as false, fraudulent, evil-sounding, offensive to pious ears, scandalous, pernicious, rash, injurious to the Church and her practice, insulting not only to the Church but also the secular powers, seditious, impious, blasphemous, suspect of heresy, and having the flavor of heresy itself, and, besides, favoring heretics and heresies and also schisms, erroneous, close to heresy, many times condemned, and finally heretical, clearly renewing many heresies respectively and most especially those that are contained in the infamous propositions of Jansen and, indeed, accepted in that sense in which these have been condemned.” (DH 2502)
Pope Pius IX later referred to these condemned errors in the following terms:
“[The ‘neo-schismatics’] follow the example of heretics of more recent times. They argue that the sentence of schism and excommunication pronounced against them by the Archbishop of Tyana, the Apostolic Delegate in Constantinople, was unjust, and consequently void of strength and influence. They have claimed also that they are unable to accept the sentence because the faithful might desert to the heretics if deprived of their ministration. These novel arguments were wholly unknown and unheard of by the ancient Fathers of the Church. For ‘the whole Church throughout the world knows that the See of the blessed Apostle Peter has the right of loosing again what any pontiffs have bound, since this See possesses the right of judging the whole Church, and no one may judge its judgment.’
“The Jansenist heretics dared to teach such doctrines as that an excommunication pronounced by a lawful prelate could be ignored on a pretext of injustice. Each person should perform, as they said, his own particular duty despite an excommunication. Our predecessor of happy memory Clement XI in his constitution Unigenitus against the errors of Quesnell forbade and condemned statements of this kind. These statements were scarcely in any way different from some of John Wyclif’s which had previously been condemned by the Council of Constance and Martin V.
“Through human weakness a person could be unjustly punished with censure by his prelate. But it is still necessary, as Our predecessor St. Gregory the Great warned, ‘for a bishop’s subordinates to fear even an unjust condemnation and not to blame the judgment of the bishop rashly in case the fault which did not exist, since the condemnation was unjust, develops out of the pride of heated reproof.’
“But if one should be afraid even of an unjust condemnation by one’s bishop, what must be said of those men who have been condemned for rebelling against their bishop and this Apostolic See and tearing to pieces as they are now doing by a new schism the seamless garment of Christ, which is the Church?” (Pope Pius IX, Quartus Supra, n. 10. 1873.)
In the face of such condemnations, what should we make of excommunications levelled by Leo XIV and his Vatican – whether against the SSPX, or anyone else?
The answer – and its implications – is found in the texts cited by the Decretum, Gratian’s comments, and the theologians who cite these texts.
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