In this article, I analyze a series of Canadian cases on union successor rights defining the circumstances in which labour rights should be transferred to a successor entity in the context of business sales, restructuring and subcontracting. This question poses itself in many legal orders, including US and European Union labour law. In carrying out my analysis, I cast doubt on a globally influential theory of legal interpretation, which I call the “old legality.” According to this theory, labour law is made not through conventional legal reasoning but through non-legal, pragmatic and purposive applications of loose industrial relations standards. I claim that the old legality paradigm is analytically inaccurate and has the perverse effect o...