The existing literature argues that the left is generally more supportive of multilateralism in foreign policy than the right. However, the impact of ideology on state commitment to multilateral cooperation have not yet been empirically tested adequately. We assess the presence of such a left–right divide on state commitment to multilateral treaties employing an original dataset, containing all the available information about the ratification of the multilateral treaties deposited with the UN Secretary General since 1945. Our results indicate that indeed countries led by left-wing leaders are generally faster at ratifying treaties than those led by right-wing leaders. However, the association between leader ideology and commitment to multilateral treaties is substantially conditioned by regime type and the international context. In fact, we find robust evidence of a significant gap in ratification duration between states led by left-wing and right-wing leaders in democracies but not in other regime types, and during the Cold War but not after. Through such findings, this article provides a contribution to the debate on the impact of ideology on international relations and the drivers of global support for multilateralism.

现有文献认为，左派通常比右派更支持外交政策中的多边主义。然而，意识形态对国家多边合作承诺的影响尚未得到充分的实证检验。我们使用原始数据集评估了国家对多边条约的承诺是否存在这种左右分歧，该数据集包含自 1945 年以来交存联合国秘书长的多边条约批准情况的所有可用信息。我们的结果表明，各国确实领导了多边条约。左翼领导人领导的条约通常比右翼领导人领导的条约批准得更快。然而，领导人意识形态与对多边条约的承诺之间的联系在很大程度上取决于政权类型和国际背景。事实上，我们发现强有力的证据表明，在民主国家中，左翼和右翼领导人领导的国家之间在批准期限上存在显着差距，但在其他政体类型中，以及在冷战期间而非冷战之后则不然。通过这些发现，本文为关于意识形态对国际关系的影响以及全球支持多边主义的驱动因素的辩论做出了贡献。