COUNTERCLAIM. — This is the action that the defendant brings against the plaintiff, thereby becoming plaintiff in the counterclaim itself. According to this general concept, the consequence follows that, in the proceedings initiated by the plaintiff, a judgment directed toward the ascertainment, discussion, and determination of the counterclaim is inserted.
But, naturally, a conception of the counterclaim so broad as to allow the defendant to bring any other action against the plaintiff is not admissible. Thus, for example, a person summoned to court by his wife for a declaration of the nullity of the marriage cannot counterclaim against the plaintiff for the restitution of a loaned sum; nor can a person summoned for eviction bring an action to disavow paternity. Clearly, it is not enough for the defendant to have any claim whatsoever to assert against the plaintiff; it is also necessary that the claim forming the subject of the counterclaim be connected with an objective element of the plaintiff’s claim, that is, that it have in common with it not only the persons (plaintiff and defendant), but also the petitum or the causa petendi, or both.
This is the concept of the counterclaim now accepted by canonical doctrine, so that, essentially, the counterclaim is a case of objective connection between actions brought respectively by the plaintiff and by the defendant (can. 1567). In truth, can. 1690, in defining the counterclaim as « actio quam reus coram eodem iudice in eodem iudicio instituit contra ectorem ad sub-movendam vel minuendam eius petitionem », seems to restrict the concept of the counterclaim to the plea of set-off and the related counterclaim. But this is only one case, a typical case, which does not exclude counterclaims based on other grounds of objective connection between the actions.
The canonical legislator, mindful of the brevity of proceedings, prevents the perpetuation of litigation by prohibiting the reconventio reconventionis (can. 1690 § 2).
The counterclaim is admitted in all contentious cases, with the exception of cases of spoliation, on the basis of the principle: spoliatus ante omnia restituendus. Can. 1691, by excluding counterclaims in criminal cases, states something that can have only historical, but certainly not scientific, significance, since everyone now knows that criminal action is public—that is, it belongs to the promoter of justice and not to the injured and reporting parties—and that therefore a reconventio criminalis is simply inconceivable. Persisting, however, in the historical recollection and still confusing the counterclaim with set-off, can. 1691 refers to can. 2218 § 3, in re criminali, whereby mutua iniuria — but only in the offenses of insult and defamation — compensatur.
The procedural effects of the counterclaim are, first of all, that the defendant assumes, with respect to it, the role of plaintiff, with the corresponding procedural obligations. The jurisdiction of the judge, even when delegated ad unam causam, is automatically extended, unless the dispute brought by way of counterclaim falls, because of absolute jurisdictional limits, within the competence of a higher judge; in that case the entire case must be referred to the latter.
The counterclaim may be brought, pursuant to can. 1630, at any stage of the proceedings at first instance, but before judgment: and this too is a serious inconvenience, which may, however, be tempered by applying the second paragraph of that same canon, namely: « Cognoscantur autem simul cum conventionali actione, hoc est pari gradu cum ea, nisi eas separatim cognoscere necessarium sit aut iudex opportunus existimaverit ». On appeal, by contrast, the counterclaim is inadmissible (can. 1891). Should an issue arise concerning the admissibility of the counterclaim, a quaestio incidens will be raised and dealt with in the ordinary form of incidental matters (can. 1837 ff.).