IO Endorsements, Perceived Alignment, and Public Support for Unpopular Policies

Abstract Recent research on international organizations (IOs) has highlighted their capacity to influence state behavior by shaping domestic public opinion, a key channel for policy change. This paper investigates an important extension of this mechanism: whether domestic leaders can proactively leverage IO endorsements to bolster support for contentious policies. Drawing on a survey experiment examining attitudes toward a controversial tax increase in Japan, we test how the effectiveness of this tactic depends on how IOs are perceived across multiple dimensions, including neutrality and expertise. Our results show that referencing IO endorsements reduces resistance to the policy. Crucially, their impact is strongest when the IO is seen as aligned with national interests. In contrast, traits such as impartiality and technical expertise—emphasized in previous studies—play a more limited role. Moreover, the persuasive power of endorsements is concentrated among government supporters, further underscoring the importance of perceived interest alignment as a critical dimension of persuasiveness. These findings offer new insights into when and how IOs shape mass attitudes and call attention to the strategic value of perceived IO biases for domestic elites.