Perjury (Lat. per, through and jurare, to swear) is the crime of taking a false Oath (q.v.). To the guilt of the sin of lying it adds an infraction of the virtue of religion. An oath properly taken is an act of worship because it implies that God as witness to the truth is omniscient and infallible. Hence the wickedness of invoking the Divine testimony to confirm an untruth is specially criminal. Prescinding from cases of ignorance or insufficient deliberation this sin is reputed to be always mortal. When in doubt one cannot without perjury swear to a thing as certain. When mental reservation is permissible it is lawful to corroborate one’s utterance by an oath, if there be an adequate cause. It is obvious, however, that if in general it be true that there is need of caution in the use of mental reservations lest they be simply lies, there will be an additional motive for care when they are to be distinguished with the solemnity of an oath. According to the common doctrine as to cooperation in another’s sin, it would be a grievous offense to require a person to take an oath when we know he is going to perjure himself. This teaching, however, does not apply to cases in which justice or necessity demand that a statement be sworn to. Hence, for instance, a trial judge may insist that evidence be presented under oath even though it be clear that much or all of the testimony is false. Perjury, according to the divisions in vogue in Canon Law, belongs to the category of crimes called mixed. These may fall under the cognizance of either the ecclesiastical or civil court, according as they are reputed to work damage either to the spiritual or civil commonwealth. No canonical penalty is incurred by one guilty of perjury, at least directly. When, however, a person has been convicted of it before a competent tribunal and sentence imposed, he is esteemed infamous (infamia juris) and therefore irregular.
JOSEPH F. DELANY