Soft law as norm-filling
Soft law can also play a norm-filling role, and stand as a complement to existing instruments (soft and hard). It can be devised and used, both in domestic and international institutions, as an interpretative device for harder instruments or to fill a gap left open by existing instruments.
It is not rare to see soft law assume this norm-filling function in the judicial realm. Courts may refer to UNGA declarations, for instance, either in situations where there are no other standards to apply, or when the binding standards are not applicable in a given case. For instance, in the case brought by Nicaragua to the International Court of Justice (ICJ) against the United States in the 1980s/1 the Court could not use the UN Charter as the basis of obligations arising for the United States.32 However, the Court decided that it could apply similar provisions, as expressed in the UN General Assembly Resolution 26 2 5.33 In that particular case, the Court referred to the soft law instrument as evidence of opinio juris in the recognition of customary international law (CIL), a point which will be addressed further in section 2.3.