The silence of the State as a unilateral manifestation of its will

During the work of the International Law Commission regarding Unilateral Acts of States, the Special Rapporteur denied that State's silence could be qualified as a manifestation of its will. Nevertheless, no theoretical reason justifies this position. The study of the practice reveals moreover that, as the case may be, State's silence can be qualified as refusal or as acquiescence and that it plays a fundamental role in the formation, the interpretation or the modification of legal interstate relations. Indeed, since it is the State's prerogative to appreciate the legality of the behavior of others States, legal certainty imposes to hold the legal relevance of their silence. Under its diverse facets, this objective constitutes the raison d'êre of the effect attributed to silence and thus allows a systematization of the various hypothesis in which it is taken into account. Depending on the situation to which it reacts, silence ensures the current or future determination of legal relations. Furthermore, the study of the conditions necessary for the production of the silence's effects reveals that positive law consecrates the theoretical possibility of qualifying silence as a legal act. International law requires, in order to attribute an effect to silence, that the silent State was free to react and had knowledge of the situation that made his silence legally relevant. Moreover, the rules governing the proof of the knowledge and of the existence of silence do not necessarily justify the criticism towards the fictive character of the voluntarist explanation of the phenomena. There is, in any event, no legal fiction in qualifying silence as a legal act