This paper offers a diachronic reconstruction of MacCormick\u2019s theory of law and of legal argumentation; in particular, two connected points will be highlighted in which the difference between the perspective upheld in Legal Reasoning and Legal Theory and the later writings is particularly marked. The first point concerns MacCormick\u2019s gradual break with legal positivism, and more specifically the thesis that the implicit pretension to justice of law proves legal positivism false in all its different versions. In brief, MacCormick uses the argument of the implicit pretension to justice of law against the thesis of the separability between law and morality and, accordingly, against legal positivism. This argument misses the target. T...