LEGAL TRANSACTION. — It is commonly defined as a private manifestation of will directed toward a practical purpose (the creation, modification, or extinction of a legally relevant situation), protected by the legal system. To clarify its notion more precisely, however, one must consider private autonomy, i.e., the power—protected by the legal system—that individuals have to regulate their own interests. When the legal system itself recognizes the social utility of a particular act of private autonomy and attaches to it legal effects through which the practical purpose desired by the private party is achieved, the transaction becomes a legal transaction (*negozio giuridico*): which can therefore be more fully defined as an act of private autonomy to which the legal system attaches effects intended to realize the socially useful function that characterizes its type (Betti).
The legal transaction constitutes the most important category of voluntary and lawful acts. The criterion for distinguishing between a legal act (*atto giuridico*) in the strict sense and a legal transaction has, according to some authors, to be sought in the fact that while the effects of the former are not determined by the parties' will, in the latter it is precisely this will that aims to produce specific legal effects. To this view, however, it has been objected that the effects of the legal transaction do not in fact arise because they are willed by the parties—who are solely concerned with achieving a practical purpose—but because the legal system, having favorably assessed this purpose, attaches to it specific legal effects. This is evidenced by the fact that in a legal transaction there may even be effects that are not willed, or at least not foreseen, by the parties.
The elements of the legal transaction are commonly distinguished (though the accuracy of this classification is debated) into essential, natural, and accidental. The essential elements are those requirements without which the legal transaction could not exist; these include, in addition to one or more competent subjects (i.e., those authorized to obtain the legal effects inherent in the regulation of interests for which the transaction is designed), the will, a form of manifestation of the will, and the practical purpose to be achieved, which is technically called the *causa*. The natural elements are those legal effects that derive from the nature of the transaction and are attached to it by law (e.g., the warranty of title in a sale), but which may be excluded by the parties' will. The accidental elements, finally, are modalities introduced by the parties' will that modify in some way the content of the legal transaction; among these, the most common are the condition (*condizione*), the term (*termine*), and the mode (*modo*).
As regards the competent subject, this is normally the holder of the interest whose regulation is sought; but exceptionally, it may differ from the holder (e.g., a guardian, curator, agent, or pledgee [see also REPRESENTATION]).
The *causa* constitutes the economic-legal function, the constant characteristic of the transaction; it must not be confused with the motive that may induce one to enter into the legal transaction (e.g., Tizio buys a house to live in), but only with the purpose that is immediately sought and that anyone entering into the transaction achieves, namely, the economic-social function of the transaction itself (in the cited case of the sale of a house, the *causa* is the exchange between the thing and the price).
The will, the central element of the legal transaction, must be genuine and serious (not, for example, made *joci causa*), and must be manifested. It is further required that there be no discrepancy between will and manifestation, as occurs, for example, when someone is compelled by violence (*v.*) to make a declaration, or in cases of error (*v.*); fraud (*v.*); mental reservation (*v.*), which occurs when a declaration that would otherwise indicate a certain intention is made while lacking such intention, and something is added that alters the tenor of the declaration, giving it a meaning different from what the circumstances would warrant (though the declarant remains bound within the limits of the declaration actually made); and finally simulation (which occurs when, in a bilateral legal transaction, the reciprocal declarations of the parties do not correspond to their actual will, in that the contracting parties pretend to enter into a transaction different from the one they actually intend to perform).
As regards the manifestation of will, this may be achieved either by the immediate realization of the purpose (e.g., the occupation of a *res nullius* or *derelicta*), or tacitly, i.e., through conduct incompatible with a will different from that deducible from the facts (e.g., one who, having been called to an inheritance, behaves as an heir is deemed to have accepted it), or by means of words, writing, or gestures.
The law also provides for cases in which recourse must be had to specific forms: formal transactions (*negozi solenni*) (for this concept and for the distinction between unilateral, bilateral, or complex legal transactions, *inter vivos* or *mortis causa*, public or private, and for distinctions particularly applicable to canon law, see LEGAL ACT).
When the constitutive elements of the transaction or its prerequisites are lacking, deficient, or otherwise defective, the legal system, depending on the case, establishes the nullity, voidability, or rescindibility of the legal transaction (see NULLITY; RESCISSION).
The theory of the legal transaction was developed by doctrine in a relatively recent period (probably in the 18th century), but the term is not used by the legislator, whether canon or civil. With regard to the positive Italian legal system, the question has been raised whether it admits the notion of the legal transaction; this question can be resolved in the affirmative, having regard to the provisions of Article 1324 of the Civil Code, under which the rules laid down for contracts apply, where compatible, also to unilateral acts having a patrimonial content; the contract is therefore, for the Civil Code, the fundamental legal transaction.
Nor is the terminology relating to the requirements employed by the legislator with the same meaning attributed to it by doctrine (see, e.g., the term *causa*, which the Code of Canon Law sometimes uses to indicate the motive, cc. 42, 84, 1233 § 1, etc., and at other times in the proper sense, c. 1087 § 2).
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