Dictum of the day, or on the arithmetic of constitutions

[C]onflict between convention and law which prevents the courts from enforcing conventions also prevents conventions from crystallizing into laws, unless it be by statutory adoption. It is because the sanctions of convention rest with institutions of government other than courts, such as the Governor General or the Lieutenant Governor, or the Houses of Parliament, or with public opinion and ultimately, with the electorate, that it is generally said that they are political [...] It should be borne in mind however that, while they are not laws, some conventions may be more important than some laws. Their importance depends on that of the value or principle which they are meant to safeguard. Also they form an integral part of the constitution and of the constitutional system. They come within the meaning of the word "Constitution" in the preamble of the British North America Act, 1867 [...] That is why it is perfectly appropriate to say that to violate a convention is to do something which is unconstitutional although it entails no direct legal consequence. But the words "constitu­tional" and "unconstitutional" may also be used in a strict legal sense, for instance with respect to a statute which is found ultra vires or unconstitu­tional. The foregoing may perhaps be summarized in an equation: constitutional conventions plus constitutional law equal the total constitution of the country.

Reference re Amendment of Constitution of Canada/Partition Reference, [1981] S.C.J. No. 58, [1981] 1 S.C.R. 753 (S.C.C.), p. 883-884.