In Law of the Constitution, A. V. Dicey identified two legal principles as the animating principles of the British constitution: parliamentary sovereignty and the rule of law. The juxtaposition of these two principles exposed central themes at the heart of the ideal of constitutionalism and constitutional government within the common law tradition. Early in his book, Dicey stated that parliamentary sovereignty is ‘the dominant characteristic of our political institutions’.1 Yet it would be clear by the end of the book that Dicey saw the two principles as equal in their importance – that supreme legislative power is valued insofar as the supremacy of law is valued. ‘Th[e] rule of law’, Dicey concluded, ‘is of the very essence of English institutions’, and ‘[i]f the sovereignty of Parliament gives the form, the supremacy of the law of the land determines the substance of our constitution’.2