Health Protection Branch

2. A Brief Introduction to Basic Principles of Canadian Constitutional Law

The primary document of the Canadian constitution is the British North America Act 1867, 30 & 31 Victoria, c. 3 (B.N.A. Act). That act together with its amendments, was and still is, an enactment of the Imperial Parliament of the United Kingdom. Among other things, the B.N.A. Act provides for a division of legislative powers between the federal and provincial governments — section 91 lists the exclusive heads of federal legislative power and section 92 lists the exclusive heads of provincial power. To determine a statute's constitutional validity, a court must establish whether or not the legislation is within the power of the enacting government. If the legislation is within the enacting body's constitutional competence, it is valid or intra vires and if it is beyond the enacting body's authority it is invalid or ultra vires.

In interpreting the B.N.A. Act, the court attempts to prevent either level of government from encroaching on the power of the other. There is in practice, if not in strict legal theory, however, a presumption of constitutional validity. In effect the court begins its inquiry by presuming the statute in question to be valid. The burden of proving otherwise is, therefore, on the party alleging invalidity. Where proper and possible the court will interpret an enactment in such a way as to make it valid. For example, if there are two alternative interpretations of an enactment, the court will adopt the one that brings it within the constitutional competence of the enacting body.¹

Basically the courts have adopted a three-step procedure for determining the validity of a statute. First the court identifies the statute's dominant feature or "matter" based primarily on its wording, purpose, effect, context, and legislative history. Merely reading a statute may not provide a true understanding of its matter. The term "colourability" is used to describe a situation in which the statute's language disguises its real nature. While the legislation appears valid, careful analysis indicates that its true matter falls within a head of power reserved for the other level of government. In such cases the doctrine of colourability is invoked and the legislation is held to be ultra vires.²

Once the court has determined the subject matter of the legislation, it must then define the scope of the relevant heads of power in sections 91 and 92. Since the sections are intended to provide an exclusive set of legislative powers and also overlap, they must be read contemporaneously. The scope of any head of power is limited by the scope of the others. This approach to interpreting sections 91 and 92 is referred to as the principle of "mutual modification."

The heads of power are not defined, but rather are briefly described in broad, general terms. The ambit of a particular power must be pieced together from the judgments in various cases. Unfortunately, few cases raising constitutional issues concerning cannabis have been litigated. Even in areas where there is some relevant caselaw, the courts have tended to base their decisions on narrow technical grounds which do not permit the extraction of fundamental principles.

The final step in the process is to determine which head of power the subject matter of a statute comes within. An enactment may incidentally effect a particular power without coming within it. This "ancillary" doctrine applies where the encroachment on the jurisdiction of the other level of government is necessarily incidental to the effective operation of the legislation in question. For example, a provincial statute may incidentally affect the federal power of banking s. 91(l5) but its matter may be within "property and civil rights" s. 92(l3).³ If the encroachment is not merely incidental, the legislation is said to be "trenching" on the power of other level of government and is ultra vires.

The power to legislate on a complex phenomenon such as non-medical drug use is unlikely to be exclusively federal or provincial. While some drug laws may fall exclusively within either federal or provincial jurisdiction, others may be within the legislative competence of both levels of government. There is concurrent responsibility for such legislation, and both levels of government could enact it. As we shall later discuss cannabis prohibition legislation may well be an example — the provinces could claim that a provincial prohibition was within their power over public health s. 92(16) and the federal government could justify their prohibition as a matter of criminal law s. 9(27). In such situations the law is said to have a "double aspect." In a classic statement of this doctrine, the court explained, "subjects which in one aspect and for one purpose fall within sect. 92, may in another aspect and for another purpose fall within sect. 9l."⁴ If Parliament and the provinces enacted cannabis prohibitions that were incompatible, the resulting conflicts would be resolved by the doctrines of "paramountcy" and "concurrency" — these principles will be examined later in the text.

Constitutional analysis is a speculative undertaking. Since legislation is given legal effect until it has been successfully challenged,⁵ constitutionally-suspect enactments may remain operative simply because other governments and private litigants have no interest in questioning them. Even if the legislation is challenged, predicting the outcome of constitutional litigation is difficult. While some boundaries of the federal and provincial legislative domain can be readily identified, many constitutional issues central to cannabis control are, and will likely remain, contentious.