판결의 반사적 효력 ― 대법원 2015. 7. 23. 선고 2014다228099 판결의 평석을 겸하여 ―

After the creditor filed a lawsuit against the principal obligor and lost the case, the creditor filed a lawsuit against the guarantor to claim the security deposit. Can the guarantor block the creditor's lawsuit to claim the security deposit by asserting that the principal obligor won the previous lawsuit? This issue can be either affirmed or denied depending on how to interpret the relationship between Article 430 (appendant nature of purpose and formality) and Article 433 (guarantor and principal obligor’s right to make defenses) of the Civil Act and Article 218 (subjective scope of res judicata) of the Civil Procedure Act. This problem can also arise when there is a dependence relationship under substantive law, such as between a partnership company and an employee or a joint debtor with absolute reasons for effect. This is a question of whether or not the reflexive effect is recognized. The Supreme Court, unlike Japanese or German precedents, denies extending the binding force of a final judgment between a creditor and a principal obligor to a subsequent action between a creditor and a guarantor. Therefore, the guarantor may lose in the subsequent suit, and this attitude is in line with the current general theory that the essence of res judicata is found in the law of litigation. However, if the losing guarantor pays the guaranteed debt to the creditor and files a suit for subrogation against the principal obligor, a judgment will be rendered requiring the principal obligor to pay the subrogation unless there are special circumstances. If that happens, the principal obligor's victory against the creditor becomes meaningless and is not in line with the provisions of substantive law. In order to prevent such inconsistency, if the guarantor uses the prevailing judgment of the principal obligor in a subsequent lawsuit, it should not be rejected as an argument to expand res judicata. By interpreting the litigation itself, which was the reason for the principal obligor's victory in the previous lawsuit, the court needs to draw a valid conclusion after conducting a substantive trial on the litigation act cited by the guarantor.