This talk by Associate Professor Li Xiaojun attempts to engage with the literature on descriptive legitimacy and applies it to understand how descriptive representation affects perceptions of international organization (IO) legitimacy. Specifically, the talk puts forward the argument that representation of an adversarial state at an IO, in the form of the nationality of its key decisionmakers, will undermine the public’s acceptance of the IO’s mandate, and that the effect will increase as the perceived threat of the adversarial state rises. Furthermore, when the adversarial state is considered undemocratic and untrustworthy, the public are more likely to view the IO as undemocratic and its decisions unfair. Consequently, the IO’s perceived legitimacy will suffer because the procedural and performance sources of the IO’s institutional legitimacy will be damaged. We test this argument empirically using a survey experiment on public perception of the legitimacy of the International Court of Justice (ICJ) in the United States, where we manipulate the nationality of the ICJ president who casts a tie-breaking vote against the United States. The results show that when the judge is Chinese, there is a strong and robust dampening of Americans’ perceptions of the ICJ’s legitimacy, with no comparable effect arising when the judge’s identity is of other nationalities. With tensions escalating in U.S.–China relations, our finding that Americans view an ICJ presided over by a Chinese judge as less legitimate has important implications for the liberal international order built upon IOs in which China is a key member.