Based on Foucaultian as well as on more traditional critical ideas, this study attempts to provide a critical and original account of the historical development of American labour law.;It is argued that only by paying attention to changes in wider legal and social discourses can we fully understand the transformations that have occurred within American labour law and which have resulted in unions ceasing to be regarded as criminal conspiracies and becoming instead the bearers of well-established but still contested legal rights.