Recent scholarship on international institutions has begun to explore potentially powerful indirect pathways by which international institutions may influence states’ domestic politics and thereby influence the foreign policy preferences and strategies of state leaders. In this paper, we provide evidence documenting the indirect impact of institutional cues on public support for the use of force through an analysis of individual-level survey data and a survey-based experiment that examines support for a hypothetical American intervention in East Timor. We find that institutional endorsements increase support for the use of force among members of the American public who value the institution making the endorsement and among those who do not have confidence in the president. These individual-level analyses show that international institutions can affect domestic support for military action by serving providing a valuable “second opinion” on the proposed use of force.