공평의 관점에서 본 상계항변과 기판력 - 대법원 2005. 7. 22. 선고 2004다17207 판결을 중심으로 -

The final decision of court has res judicata as an effect. Res judicata reaches not the reason for decision but the main judgment for claim of action itself. The only exception is the judgment for counter argument based on setoff in the reason for decision. The 2004Da17207 decision (hereinafter “the Decision”) rendered by the Supreme Court (hereinafter “the Court”) on July 22, 2005 made an exception for such exception, where the court held that res judicata does not occur to the judgment for rebuttal based on setoff against the counter argument based on concurrent fulfillment. The Court stated that both the equity between parties and the effectiveness of the court decision are why res judicata is acknowledged for the judgment for counter argument based on setoff. Such statement is fair and persuasive. The Court required the object of the counter argument based on setoff to be either the claim of action or its equivalent in order for the judgment for such counter argument to be covered by res judicata. Such requirement is correct. From such requirement could the functional relation be inferred that the judgment for the object claim (i.e. ‘the claim of action’) of the counter argument based on setoff is an independent variable and the judgment for such counter argument is a dependent variable. The conclusion of the Decision is also right. However, the reasoning through which the Court reached the conclusion can be subject to criticism. The reasoning does not only distort the functional relation above but also lacks its own basis. The issue of the counter argument based on setoff and res judicata has both sides. For one, if the judgment for object claim of counter argument based on setoff is reached by res judicata, the counter party of the party who made such counter argument needs to be protected by granting res judicata for the judgment for counter argument based on setoff. For the other, if the judgment for object claim of counter argument based on setoff is not reached by res judicata, the party who made such counter argument needs to be protected by not granting res judicata for the judgment for counter argument based on setoff. The approach based on equity between both parties needs to be taken. Even though the Decision is a case where the party who made rebuttal based on setoff against the counter argument based on concurrent fulfillment may well be protected, the Court made an improper reasoning by taking an opposite approach in protection for the counter party who made such counter argument.