Extensive interpretation of legal provisions is in tension with the prohibition of reasoning by analogy in criminal law, for it is unclear what the difference is between the two. Some scholars claim that they differ from a theoretical point of view, since they do not have the same argumentative structure. On the other hand, the two come to the same result starting from the same legal materials: they justify the extension of a regulation to a case that is not explicitly considered by the law. The paper deals with this issue discussing a recent Italian case (the "Vatican Radio case") and proposes an account of the distinction between the two based upon the principle of semantic tolerance and its inferential structure in legal argumentation.