BACKWARD OPERATION OF THE LAW. — The Code of Canon Law has adopted the principle of the non-retroactivity of the law, establishing that leges respiciunt futura, non praeterita, nisi nominatim in eis de praeteritis caveatur (can. 10). This principle, common to every legal system, is one of those of intertemporal law which seeks to provide a criterion for resolving cases in which a new legal norm, regulating a matter already subject to other provisions, finds itself confronted with relationships that began under the old law and reached their completion under the new, or which, established under the old norm, assert their effects during the period of the new.
Among modern canonists, whose attention has been drawn by the cited norms of the Code and by those of can. 4, which expressly mentions the iura aliis quaesita by establishing that... integra manent, nisi huius Codicis canonibus expresse revocentur, some have given to the principle the value of an absolute limit to the efficacy of the norm. Others have emphasized the purpose of the law, which is one of the many aids to which the interpreter must resort, but this presents the serious lacuna of not specifying how the interpreter should act when the purpose is not clear; still others have adhered to different and varied theories. The truth is that every doctrine has a certain foundation, and the key to the entire problem can only be found by taking from each theory the part that is true. Indeed, first of all it is necessary to distinguish, within the so-called principle of the non-retroactivity of the law, two fundamental aspects that must be kept well separate: the pre-legislative or de iure condendo aspect, and the legislative or de iure condito aspect. Regarding the former, it must be said that this is an ethical limit—one of many that are imposed upon the lawgiver—and it is a question of value that cannot be ignored by any legislator, and especially not by the canonical one; for the authority that governs every society finds an ethical limit to its governing powers in the good of the subjects, not only as a whole, but also as individuals, in the sense that legislative enactments must not, except when the common good itself so requires, harm the individual and the sphere of good that he has secured for himself through his conduct, in conformity with the precepts established by the legislator himself. Indeed, from this pre-legal perspective, already BARTOLUS DE SASSOFERRATO (In primam digesti veteris partem Commentaria, Venice 1585, tit. de iustitia et iure, 1. omnes populi), in resolving a very interesting case of a city that, after having granted tax exemption to those who would immigrate into it, wished to revoke the provision even to the detriment of those who, enticed by the exemption, had settled there, spoke of a «quasi contract» between the subject of the law and those who had enacted the law, expounding a concept entirely in conformity with the informing concept of the principle of the non-retroactivity of the law. Under the other aspect, however, the principle, as a directive for those who must apply the law, consists entirely in determining which law governs a concrete legal relationship that extends over a particularly vast span of time, but the Iberian peninsula is the land where retroactivity has the greatest diffusion, being one of the characteristic elements of its long history of worship. Some take up the architectural themes of the amb
There is, however, a third hypothesis: namely, that the legislative norm presents uncertainties in the precise determination of its sphere of validity. In such a case, among the various aids that interpretation has for arriving at the discovery of the legislator’s intention, there is the consideration that, in light of those pre-legal criteria recalled above, the legislator intended to regulate the future and not the past. In other words, the scope of the principle examined in can. 10 is nothing more than the reaffirmation, within the positive legal sphere, of the fundamental generic program that the legislator set for himself in issuing legal norms. Thus, where interpretation otherwise fails to grasp the will of the law, one must recall this program and, by legislative obligation, hold that the new norm is not to govern past relationships. It is only at this point that the practical problem arises of determining what is meant by *retroattività della legge* in order to apply the principle of non-retroactivity willed by the legislator. At this stage, all the doctrines recalled, and the case law—if numerous—are unanimous in holding that the validity of a juridical act must be assessed in conformity with the prescriptions in force at the time when the act itself was performed.
The problem becomes more delicate when the new law does not confront already concluded relationships, but pending ones—whether because it concerns a composite fact in which only some of its constituent elements have been realized, or a fact that is perfected only through the passage of a determinate period of time, or because a relationship already validly established continues its execution even into the time subsequent to the enactment of the new law. In the first two cases, doctrine has provided a satisfactory solution, holding that for cases of pendency arising from the non-completion of the relationship, the efficacy of the new norm is made explicit. More difficult, however, is the solution when it comes to the so-called successive relationships; here, given the centuries-old canonical practice, one must hold that the only criterion that can be invoked is that of *diritto quesito*, adopting it not in antithesis to the objective criterion of the completed fact—as some canonists have sought to do—but as a complement to and integration of that criterion.
Canon 4, which establishes respect for *diritto quesito* (q.v.)—and which constitutes a transitional norm for the internal order, just as can. 3 establishes such respect for the external order—has a different value in the norm of can. 10, inasmuch as the latter applies to all legislation, whereas the former limits its efficacy to the scope of the *Codex Iuris Canonici*. Yet this does not prevent the two provisions from being integrated as follows: “laws govern the future and are not retroactive, that is, they do not impair rights already acquired before they entered into force.”