DOLO. - The term d. is used in law with two different meanings: as a defect of the will in juridical acts, or as the subjective element of illicit acts, especially of crimes (v.).
1. In the first meaning the d. (more properly called dolus malus, as opposed to dolus bonus) consists in tricks, maneuvers or artifices used to deceive someone so as to induce him to perform a juridical act which, had he not been deceived, he would not have performed (dolus causam dans), or would have performed only on more advantageous conditions (dolus incidens).
It constitutes, together with error and violence, one of the three fundamental defects of the will, which can produce the nullity or annullability of a juridical act. In reality it can also be considered a subspecies of error, qualified by the circumstance that the error is caused by another's deceit; and in fact the principles and norms relating to d. come into consideration especially in cases in which the error deriving from it is not such as to invalidate by itself alone (that is, independently of the fact of being the fruit of another's d.) the juridical act.
An act performed through another's d. is generally not null, but only annullable (v. NULLITÀ): that is, the person who has been deceived or his heirs (and, for certain acts, any interested party) may, within a certain term (in Italian law, five years; canon law refers to civil law) from the discovery of the d., ask the judicial authority that the act be annulled. This, however, holds only if it is a matter of d. causam dans, such that, had the d. not been present, the act would not have been performed; if instead it is a matter of d. incidens, the act is valid, without prejudice to the obligation of the author of the d. to compensate the damages (CIC, cann. 103 § 2 and 1684-85; Italian Civil Code arts. 624, 1439-46). In cases in which the author of an act could ask for its annulment on grounds of d. (that is, he has, as it is said, the action of d.), he may also plead the d. (that is, he has the exception of d.) should he be summoned to court to fulfill the obligations deriving to him from the act (thus expressly can. 1686).
It should further be noted that civil law generally, in bilateral juridical acts (v. ATTO GIURIDICO), gives no relevance to d. unless it is used by one of the two contracting parties to the detriment of the other, or if, although used by a third party extraneous to the contract, it was known to the contracting party who benefits from it (cf. art. 1439 of the Italian Civil Code).
To the principles set out above the law sometimes derogates in relation to certain kinds of juridical acts. The derogation may occur in two different ways: either in the sense of considering acts vitiated by d. null, and not merely annullable (but this almost never happens), or in the sense of considering them entirely valid (that is, not even annullable). A very important example of this second derogation is found in canon law and in almost all civil legislations as regards marriage: in it, in fact, d., even if used by one of the contracting parties to the detriment of the other, does not affect the validity of the act; only the error deriving from the d. can be a cause of nullity (for civil laws, also of annullability) of the marriage, but provided that it is such that, independently of the d., it would by itself have produced such invalidity (v. ERRORE).
2. In the matter of illicit acts, one speaks of d., as opposed to fault (v.), when the author of an illicit act has acted with the intention of producing the damage or the danger in which the illicit act consists.
Outside the field of criminal law illicit acts are taken into consideration especially for the effects of the obligation, which derives from them, to compensate the damage. And since such an obligation exists both if the illicit act is committed with d. and if committed only with fault in the strict sense, the distinction between d. and fault is not of great importance: it may be said that it has relevance only to this effect, that, when two persons stipulate between themselves a pact that exempts one of them from the obligation to compensate the damages which he causes to the other, such a pact, if stipulated before the illicit act is committed, is null insofar as it concerns damages caused through d., that is, the so-called pactum de dolo non praestando is null (and in modern law, on the basis, moreover, of Roman law, gross fault is equated with d.).
The distinction between d. and fault is instead of very great importance in criminal law since many facts constitute a crime only if committed with d. (v. DELITTO). For the moral aspect v. FRODE.
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