How do leaders address the world in service of international cooperation, and do their messages enhance or detract from the global agenda? Leaders increasingly appear at the United Nations General Assembly (UNGA), a deliberative forum meant for diplomacy, not politics. At the same time, the UNGA has long undergone revitalization efforts, and leaders’ contributions could potentially ensure more meaningful cooperation. Building on theories of leader communication, we argue that, in contrast to other country representatives, heads of state have more leeway to deviate from the assembly’s priorities; as politicians, they have incentives to discuss their own, more particularistic, topics. Drawing from novel data on leaders’ speeches in the UNGA, we use text analytics to show that leaders tend to depart from the policy agenda of the session. Furthermore, national political leaders speak more plainly, centering speech on themselves and departing from the general conventions of diplomatic debate. This suggests that, while leaders’ attendance potentially generates more publicity and visibility for the UNGA, their contributions may also undermine the general debate. Our findings shed light on the ways in which leaders can politicize mulitlateral cooperation, and we give evidence for the role of individuals in the vitality of international organizations.

领导人如何为国际合作向世界发表讲话？他们的信息是增强还是削弱了全球议程？领导人越来越多地出现在联合国大会（UNGA）上，这是一个旨在外交而非政治的审议论坛。与此同时，联合国大会长期以来一直在进行振兴努力，领导人的贡献有可能确保更有意义的合作。基于领导人沟通理论，我们认为，与其他国家代表相比，国家元首有更大的余地偏离大会的优先事项；作为政治家，他们有动力讨论自己的、更具体的话题。根据领导人在联合国大会演讲的新数据，我们使用文本分析来表明领导人往往偏离会议的政策议程。此外，国家政治领导人讲话更加直白，讲话以自己为中心，脱离了外交辩论的一般惯例。这表明，虽然领导人的出席可能会为联大带来更多的宣传和知名度，但他们的贡献也可能会破坏一般性辩论。我们的研究结果揭示了领导人如何将多边合作政治化，并为个人在国际组织活力中的作用提供了证据。