Two kinds of cooperation with evil must be avoided. The first is called formal cooperation, which occurs when the cooperator shares the evil intent of the actor. Formal cooperation with evil is always morally wrong, but it is an unlikely problem for a judge who must apply the law impartially – that is, without adopting, as the judge’s own end, the object sought by a party who seeks relief from a court.
The other (and, for a judge, more likely) kind of cooperation with evil is called material cooperation. Material cooperation occurs when the cooperator assists the actor by performing an act that is not necessarily evil. Whether material cooperation is morally acceptable depends on whether there is a sound reason for the cooperation (such as avoiding a worse harm), whether the cooperation is remote or proximate, and whether the cooperator avoids the danger of scandal. The graver the evil, then the more serious the reason for cooperation must be to be justifiable.
Two of these conditions for material cooperation are ordinarily satisfied in the performance of judicial work. First, a judge has more than a good reason to apply the law impartially in every case, because the performance of that duty in a constitutional republic is a fundamental safeguard for the protection of human liberty. The resources of the judiciary are also scarce, so a judge is ordinarily obliged to perform his share of the work of the judiciary. Second, the performance of the judicial function is likely to be remote from the intended evil act of the party before the court; the typical scenario is where the judge determines that the law does not empower the government to interfere with a third party’s choice to commit an immoral act.
A judge needs to be attentive to the third condition for acceptable material cooperation: avoiding scandal, which the Catechism defines as “an attitude or behavior which leads another to do evil.” The Catechism explains that “[a]nyone who uses the power at his disposal in such a way that it leads others to do wrong becomes guilty of scandal and responsible for the evil that he has directly or indirectly encouraged.” The Catechism also states that “[s]candal can be provoked by laws or institutions, by fashion or opinion.” For judges and lawyers there is a special danger of scandal, because “[s]candal is grave when given by those who by nature or office are obliged to teach and educate others.”