The legitimacy of international institutions has in the last years come under increasing scrutiny both in public and academic debate. One critique that is often voiced, for example against the European Court of Human Rights (ECHR), is that international institutions overstep their given mandates. How should we evaluate these charges? How does the legitimacy of international institutions depend on their mandate and how can they legitimately change? This paper suggests distinguishing between three different dimensions of international institutions’ legitimacy. These fundamental aspects of legitimacy are: 1) the institution’s purpose, 2) its creation, and 3) the political power or competencies that it exercises. It discusses whether the often-used standards of state consent, democracy or service are appropriate with regard to these legitimacy aspects. Since the dominate standard for the creation of international institutions, namely state consent, is not normatively unproblematic, the other dimensions such as the importance of the institutions’ purpose have to be taken into account too. The second part of the paper illustrates how these theoretical considerations bear on legitimacy assessments of specific international institutions on the example of international courts. It shows how the theoretical framework helps to understand and to evaluate legitimacy challenges that have been leveled against the ECHR.
