It is customary for legislation to include a preamble, in which certain background facts or circumstances are recited or noted.3The first recital of the preamble to the Constitution Act, 1867 states that the provinces of Canada, Nova Scotia, and New Brunswick "have expressed their Desire to be federally united into One Dominion under the Crown of the United Kingdom ... with a Constitution similar in Principle to that of the United Kingdom." Three fundamental aspects of the Canadian constitutional order are highlighted by this recital. First, Canada is a federal as opposed to a legislative union; that is, jurisdiction is divided between the federal government and the provincial orders of government, each order having constitutional recognition and significance. Second, Canada is "one Dominion under the Crown of the United Kingdom." That is, Canada is a constitutional monarchy, as opposed to a republic, and the Crown is the formal head of state. Third, Canada has a constitution "similar in Principle" to that of the United Kingdom. The precise meaning of this phrase is far from clear, particularly because the British constitution is largely unwritten. The preambular reference to the British constitution must mean, at the very least, that the Canadian constitution is itself partly unwritten. The drafters of the Constitution Act, 1867 signalled that it would be impossible to understand the actual workings of the institutions of the Canadian state simply by reading the terms of the Act itself.
One obvious example of the unwritten character of the Canadian constitution is the principle of responsible government, which, as discussed in Chapters 1 and 2, requires that the powers of the Crown be exercised on the advice of persons who enjoy the confidence of the elected chamber in the legislature. The principle of responsible government was not explicitly referred to anywhere in the Constitution Act, 1867. But responsible government had been accepted by both Brit-
ish and colonial...