복수의 상계항변에 관한 판결의 기판력 - 대법원 2018. 8. 30. 선고 2016다46338, 46345 판결 -

While Article 216(1) of Korean Civil Procedure Act provides that the matters contained in the text of a judgment shall have the effect of res judicata, Article 216(2) creates an exception for decisions regarding the existence of the defendant’s claim raised in set-off, specifying that such decisions shall only have the effect of res judicata with respect to the “amount pleaded to offset”. This exception arises from the nature of an independent or legal set-off, as a procedural defense, enabling the defendant to ‘realize’ its claim by discharging the plaintiff’s claim through the civil procedure. Therefore, ‘amount pleaded to offset’, in reference to the scope of res judicata, should be interpreted in light of the rationale underlying this exception. The Supreme Court of Korea in its decision of August 30th, 2018, articulated the principle that the res judicata effect concerning a defendant’s claim which the court has determined to be nonexistent, shall not exceed “the remaining amount of the plaintiff’s claim” after the set-off with the defendant’s claims which the court has determined to exist. In certain circumstances, however, this principle may be in conflict with the purpose of res judicata, which is to prevent the double exercise of rights. When multiple claims of a defendant are raised in set-off, the court must decide each claim in accordance with the order of appropriation established by the law. In some cases, a defendant’s claim, which could have been set-off first but was decided to be nonexistent, may have discharged the claim in an amount exceeding the ‘remaining amount of the plaintiff’s claim’. This creates a contradiction with the intended purpose of res judicata. Therefore, the principle stated by the Supreme Court warrants reconsideration in order to avoid such contradictions and to better align with the purpose of res judicata.