Cueing Foreign Elite Consensus or Divisions: The Effect of Unanimity in International Organizations on Public Opinion

How do international organizations (IOs) affect public opinion? Recent scholarship shows that members of the public tend to be rationally ignorant about international affairs and form an opinion by observing unity or disagreements among well-informed and trusted elites. Building on that insight, this study argues that the effect of IOs on public opinion depends on whether they signal consensus or divisions among member states’ representatives. Specifically, unanimous policy decisions signal consensus among international elites in support of a policy, which rallies support for the policy among members of the public who trust the organization. In contrast, approval despite vocal dissent or non-approval due to vetoes cue divisions between international elites, and they do not increase the public’s support. Five survey experiments administered to representative samples of American and German citizens between 2016 and 2020 test this argument in the issue areas of security and immigration. They show that the unanimous endorsement of a U.S. military intervention by the UN Security Council increases American popular support for the use of force by six to ten percentage points, in comparison to the Council’s approval of the same action despite dissent. Additional survey experiments find that unity or divisions in the Council of the EU on refugee resettlement have a similar effect on German public opinion. Causal mediation analyses provide evidence on the mechanisms at work. These findings challenge the literature on international organizations and public opinion, which conceives of the signals conveyed by these institutions as dichotomous (policy support or opposition) and therefore does not distinguish between cues of unity and divisions among international elites.