Acts of international organizations often reflect developments in international law. Therefore, they could contribute to the evolutive interpretation of treaty texts if it were not for Article 31 VCLT, which embraces extraneous material for interpretative purposes but strongly focuses on the parties’ acceptance of the material’s interpretive value. The analysis of national and international case law shows that acts of international organizations are very rarely mentioned in the context of treaty interpretation and very little use is made of the opportunity to establish the ordinary meanings of technical treaty terms through such acts. The organizations’ most important interpretive role lies in the self-application of their constituent instruments, and even then, only with respect to so-called ‘household matters’ concerning each organization’s own procedures and competences. In contrast, the functional authority of organizations concerning the interpretation of the ‘constitutional’ rights and obligations of their Member States requires the latter’s broad acceptance. With regard to treaties other than constituent instruments, the analysed case law illustrates that domestic and international courts continue to demonstrate great reluctance in using the acts of international organizations in their interpretive processes and, when they do, they do so in a faltering manner.

国际组织的行为往往反映了国际法的发展。因此，如果不是 VCLT 第 31 条，它们可能有助于条约文本的演变解释，该条包含用于解释目的的无关材料，但强烈关注缔约方对材料解释价值的接受。对国内和国际判例法的分析表明，国际组织的行为很少在条约解释的背景下被提及，也很少利用通过此类行为确立技术性条约术语的普通含义的机会。各组织最重要的解释作用在于其组成文书的自我应用，即便如此，仅针对涉及每个组织自己的程序和能力的所谓“家庭事务”。相比之下，组织在解释其成员国的“宪法”权利和义务方面的职能权威需要后者的广泛接受。关于除组成文书以外的条约，分析的判例法表明，国内和国际法院在解释过程中继续表现出非常不愿意使用国际组织的行为，并且在使用时，它们以蹒跚的方式使用。