The application of informal international instruments before domestic courts

The rigidity associated with formal international law has induced states and international organizations to resort to declarations, comments, guidelines, and other "informal" international instruments. Despite their informality, many of these nontreaty instruments have prompted actions at the domestic level, including before domestic courts. This Article analyzes on what basis domestic courts apply informal international instruments. Given that the "bindingness" is not always available as an explanatory factor, the normative basis for giving effect to informal instruments has to be found in the persuasiveness of instruments. Yet, what makes a particular instrument persuasive in the eyes of a domestic court remains unclear. The uncertainty in the notion of persuasiveness on the one hand empowers domestic courts in the development of international norms. On the other hand, the uncertainty renders unstable the legitimacy of judicial engagement and generates the varied judicial amenability to informal international instruments.