Regarding the appeal trial of the independent party intervention lawsuit

Independent party intervention is a system to resolve disputes between the three parties without contradiction in a single litigation procedure, and this union dicision should not only mean ‘preventing contradictions between judgment conclusions’, but also ‘preventing contradictions between judgment reasons’. Therefore, in determining whether a losing party's claim without appeal is subject to an appeal trial, the ‘possibility of contradiction between the conclusions of the judgment’ should not be the standard, and it should be judged based on ‘whether it is incompatible with the claim of the losing party who appealed’. The Supreme Court's July 28, 2022 sentence of 2020 Da231928 (the judgment of the subject of the study) presents the legal principle that the subject of the appeal trial and the exclusion of the principle of prohibition of change of disadvantage are determined on the basis of the ‘necessity of union decision of conclusions’, and seems to be in the position that the union decision, which is the purpose of the independent party intervention system, only means ‘preventing contradictions in the conclusion) of the judgment’. However, even though the judgment of the subject of the study was a case in which there was no possibility of contradiction in the conclusion of the judgment, it was judged that the claim of the losing party who did not appeal was also subject to the judgment of the appeal trial. In light of this, it seems that the judgment of the subject of the study actually applies the criterion of ‘whether it is incompatible with the claim of the losing party who appealed’. In the end, it is not clear which position the judgment of the subject of the study has taken regarding the meaning of union decision. If the Supreme Court wants to draw the above conclusion regarding the subject of the appeal trial in the future, at least, the legal principle that “the subject of judgment of the appeal trial is limited to the scope of objection shown in the contents of the appeal of the person who filed the actual appeal, but the scope of the judgment should be judged in consideration of the necessity of union decision of conclusions between the three parties” requires amendment such as deleting the expression “conclusion”.