Living Constitution - Internationally

Internationally

In Canada, the living constitution is described under the living tree doctrine.

Unlike the case of the United States, the fact that the constitution of Canada was intended from the outset to encompass unwritten conventions and legal principles is beyond question. For example, the text of the constitution does not mention the office of prime minister or that the governor general always grants royal assent to bills. Principles such as democracy, the Implied Bill of Rights, the rule of law, and judicial independence are held to derive in part from the preamble of the constitution, which declared the constitution of Canada to be "similar in principle" to that of the United Kingdom.

The concept of an evolving constitution has notably been applied to determine the division of powers between provinces and the federal government in areas of jurisdiction not contemplated at the time of enactment of the British North America Act. For example, authority over broadcasting has been held to fall within the federal "peace, order and good government" power.

The Supreme Court of Canada, in Re: Same-Sex Marriage (2004), held that Parliament (as opposed to provincial legislatures) had the power to define marriage as including same-sex unions. It rejected claims that the constitutionally enumerated federal authority in matters of "Marriage and Divorce" could not include same-sex marriage because marriage as conceived in 1867 was necessarily opposite-sex:

The "frozen concepts" reasoning runs contrary to one of the most fundamental principles of Canadian constitutional interpretation: that our Constitution is a living tree which, by way of progressive interpretation, accommodates and addresses the realities of modern life.

It has been argued that a primary determinative factor in whether a legal system will develop a "living constitutional" framework is the ease with which constitutional amendments can be passed.