Venturini, G. Keywords: Unilateralism | Public international law | Mots clefs: Unilatéralisme | Droit international public | ABSTRACT In the most recent doctrine, Gian Carlo Venturini points out in 1964 that there is a tendency to recognize the eligibility, in the international legal order, of institutions specific to certain systems of domestic law, such as estoppel and acquiescence, which assign legal effects to the attitude of States, while doubts still arise as to the legal value of the unilateral acts themse…