INTERVENTION IN PROCEEDINGS. – The entry into the procedural relationship of a third party who was a stranger to it at the time when it arose (can. 1852).
I. in p. is of various kinds. First, it is voluntary or compulsory (can. 1853), according as it is effected on the spontaneous initiative of the third party or at the request of one of the parties or by order of the judge. In turn, voluntary i. in p. is distinguished as principal, accessory and liticonsortial, according as it is made ad excludendum iura utriusque competitoris or ad adiuvandum, or on the simple assumption that there is a fear that the judgment may cause prejudice to the intervening party just as it would cause prejudice to the party to which, as a result of the joinder of parties, the intervening party would become bound.
More particularly, principal i. in p., like accessory intervention by joinder, presupposes the following conditions: that there be a third party, that proceedings be pending in which the third party intends to intervene, that the third party have an interest in intervening and, finally, that the judge seised of the already pending case have jurisdiction to hear the intervening party’s claim. It should be noted that, as regards the element of interest, it is sufficient that this be juridical, that is, arising from the incompatibility, owing to the identity of petitum and causa petendi, between the right asserted by the third party through the i. in p. and that pleaded in the proceedings by the parties. Since in this case the i. in p. is voluntary, it is evident that the third party’s rights remain unaffected if it is not undertaken.
In accessory or simple intervention by joinder, the third party has standing that is not autonomous but derivative. That is, it operates in relation to the judgment already existing between the parties, or rather in relation to the defence advanced by one or some of them, so that the third party would not have standing, in separate proceedings, to proceed against the opposing party of the one in whose aid it proposes its intervention.
Finally, in autonomous intervention by joinder or litisconsortial intervention, the third party intervenes in order to assert a right dependent upon the petitum or the causa petendi already pleaded in the proceedings; but, unlike in principal i. in p., it does not submit two distinct claims against the two parties to the proceedings, but a single claim against one of them; and, unlike in intervention by joinder, it has autonomous standing, enabling it to assert its right even in separate proceedings.
In the two forms of compulsory i. in p. (at the request of a party or by order of the judge), the third party’s initial procedural conduct is characteristically passive. In compulsory i. in p. at the request of a party, as a rule, each party’s interest in the case in having the proceedings extended to the third party arises either from the fact that it considers the case to be common to the third party, owing to the identity or connection of objective elements, or from the fact that the third party has undertaken to guarantee the interested party the right asserted in the litigation. Compulsory i. in p. by order of the judge, on the other hand, has no condition other than the judge’s discretionary assessment of the proceedings, such that it may seem appropriate to him, for reasons of procedural economy and with the aim of eliminating the danger of contradictory judgments, once the pending case has for any reason been deemed common to the third party, to order the latter’s summons. This form of compulsory i. in p. usually occurs in cases involving the public interest and, since according to the majority of authors it has merely evidentiary purposes, it may also be effected at the appellate level.
In the first case, and on this point doctrine is in agreement, intervention is lawful when it is justified by a particular conventional norm. Of particular interest in this regard are those treaties establishing a system of control or an economic-financial regime among States, very numerous either already in force or under consideration in recent times, and in which an attempt is also made to find a common basis upon which to construct an international, or for the moment merely European, community. In addition to particular treaties, intervention may be contemplated by treaties of a general nature: typical among these was the Covenant of the League of Nations, officially dissolved on 18 Apr. 1946 following the creation of the Statute, or Charter, of the United Nations, signed by fifty States on 26 June 1945 and entering into force on 24 Oct. of the same year.
Furthermore, intervention may be determined by a general international norm. Thus doctrine examines whether injury to another’s right may become lawful or not prohibited when connected with self-help, legitimate self-defence, and a state of necessity. The lawfulness of intervention is generally recognized when it is the consequence of a violation of a subjective right of the intervening State committed by the State against which the intervention is directed. The same may be said of intervention caused by legitimate self-defence, that is, in cases where the territory, citizens, or property of the intervening State are to be protected. It is disputed whether intervention can be legitimized by a state of necessity, since the assessment of the seriousness of the threat affecting the intervening State is made by that State itself, and may therefore conceal a political rather than a legal necessity.
In the second case, that is, when intervention is directed not to the defence of subjective rights but of mere international interests, the real problem of its admissibility or lawfulness arises, in view of the numerous actions of States that exert pressure on the conduct of another State in order to compel it to adopt behaviour conforming to their interests, without any legal title.
Two opposing theories contend for the field. One, called the general theory of intervention, regards intervention as a lawful means of protecting international interests, even without a legal title permitting II. This theory may be challenged on the ground that it has not yet been possible to demonstrate the existence of even a single interest for whose protection a State is authorized by international law to injure another’s right. An act of this kind would not only oppose the fundamental right to liberty, but would also violate international justice and order, which have their foundation—or rather their juridical character—in universal natural law.
The other theory, defined as the general theory of non-intervention and condemned by Pius IX (allocution Nocax et ante of 28 Sept. 1860, Syllabus, prop. LXII), regards as unlawful, in homage to respect for the sphere of freedom left to every State by international law, any intervention not founded upon a legal title (whether this be a general norm of international law or a special conventional norm), and denies the possibility of constructing intervention juridically as a means of protecting interests not recognized by international law. In homage to the uncertain positivist spirit informing the present international legal order, intervention could not even be justified on humanitarian grounds, that is, in cases where the fundamental rights of human beings were violated. To this erroneous principle of non-intervention it may be objected that, when there exists a serious and reasonable cause, which must certainly not be reduced to the defence of a pure and simple interest, it is lawful—and in some cases even obligatory—to intervene in the internal and external affairs of other States.
Intervention may be carried out in extremely varied ways, but in general it must be borne in mind that the acts through which it is effected must always conform to customary or particular international law.
Intervention, which properly consists in the use of coercive means or in the threat of resorting to them, must be distinguished, for example, from the offer of mediation, protests made through diplomatic notes, the breaking-off of diplomatic relations, and so forth; finally, intervention cannot and must not be identified with war, which is an institution in itself, both because of the causes that may bring it about and because of the manner in which it must be conducted, as well as its effects.
Historically, the principle of non-intervention was first enunciated in the Peace of Westphalia, signed on 24 Oct. 1648, though only with regard to religious conflicts. The implementation of this principle in the specifically political sphere occurred when, toward the end of the eighteenth century, France, born of the Revolution, sought to react against the intervention of the European Powers aiming to restore the French monarchy. It was studied in particular during the first half of the nineteenth century, when the members of the Holy Alliance sanctioned its lawfulness in cases where revolutionary movements in other States endangered the legitimate principles.
The attempt to intervene in favour of Spain against the revolutionary movements of the South American colonies provoked President Monroe’s message of 2 Dec. 1823, which gave rise to the doctrine of the non-intervention of the European Powers in American affairs, while reserving to the United States of America the power to intervene in the affairs of the other American States. In the second half of the nineteenth century, interventions occurred particularly against religious oppression and the oppression of ethnic minorities. In the period closer to our own, intervention tended also to change its form: from armed intervention it generally became diplomatic, only to become armed again in the First World War of 1914–18. In our own times, from the beginning of the Second World War onward, a distinctly interventionist programme can be observed which, after the end of the war, assumed various forms (economic, political-military aid, etc.).
Nevertheless, the general principle of non-intervention was once again enunciated in art. 2, no. 7, of the Statute of the United Nations (1945): “Nothing contained in the present Statute shall authorize the United Nations to intervene in matters which are essentially within the domestic jurisdiction of any State.” This principle has received renewed confirmation from the events taking place in these very latest times in Korea.