Assuming that effective governance refers to the state’s regulatory powers over private natural and legal persons, it is fair to say that it has been the poor cousin of constitutionalism. Liberal constitutional thought has been largely preoccupied with the need to restrain executive power rather than to justify it.1 That was true first of its focus on royal prerogative power, later of its antagonism toward rule by executive decree or legislation, and into the twentieth century of its uncertain aversion to regulation. Those theorists and public lawyers that resisted that narrative of ‘constraint’, predominantly on the social democratic left, would for the most part choose the language of democracy as their contrarian justificatory framework.2 The contest has similarly played out across the twentieth century in British constitutional thought through an argument between parties who align themselves, roughly put, with one of two supposedly competing principles at the core of the British constitution: the sovereignty of Parliament and the rule of law.3 None of the parties to that dispute are concerned to make the case for executive power per se.