In contemporary debates in legal reasoning Professor Manuel Atienza has coined a term which has gained certain notoriety amongst theorists of legal argumentation: “the standard theory of legal argumentation”. Despite the relative success of the term, there is some controversy about two connected questions: its allegedly usefulness, on one hand; and the kind of argumentative models that could be included in it, on the other. This paper purposes to answer both questions by claiming that Atienza's argumentative model might be an instance of a “standard theory”, but only if it is understood in a way that is “external” to the model of Kantian rationality. At the same time, this argument will show that the term is useful for improving legal reasoning theories.