Arnold Pronto is a Senior Legal Office at the United Nations Office of Legal Affairs and a Member of the Secretariat of the International Law Commission. His article discusses the “Hard/Soft” distinction in international law. A common characterization employed in contemporary international law is that between “hard” and “soft” law. A determination that an instrument falls into either category carries with it a series of implications, including that pertaining to the legal consequence of noncompliance with the rules contained in the text. What is at times overlooked is the relatively common phenomenon of the two types of law co-existing, where hard rules provide the context or the limits (boundaries, ceilings, and floors), and the details are “filled-out” by soft rules. A full appreciation of the resulting legal picture requires not only a familiarity with both types of rules but also an understanding of how they relate to each other. This is explored on two levels: the relative “authoritativeness-deficit” of the distinction under international law, and the reflection that the ambiguity inherent in the distinction reveals not two, but four, possible outcomes.