Canadian Western Bank v Alberta

It was emphasized by the Court that all constitutional legal challenges to legislation should follow the same approach:

1. the pith and substance of the provincial law and the federal law should be examined to ensure that they are both validly enacted laws and to determine the nature of the overlap, if any, between them.
2. the applicability of the provincial law to the federal undertaking or matter in question must be resolved with reference to the doctrine of interjurisdictional immunity.
3. only if both the provincial law and the federal law have been found to be valid pieces of legislation, and only if the provincial law is found to be applicable to the federal matter in question, then both statutes must be compared to determine whether the overlap between them constitutes a conflict sufficient to trigger the application of the doctrine of federal paramountcy.

If the constitutionality of legislation is being questioned in relation to the division of powers under the Constitution Act, 1867, an analysis of its pith and substance must be undertaken. There is an inquiry into the true nature of the law in question for the purpose of identifying the matter to which it essentially relates.[2]

• If its pith and substance can be related to a matter that falls within the jurisdiction of the legislature that enacted it, the courts will declare it intra vires.
• If, however, it can more properly be said to relate to a matter that is outside the jurisdiction of that legislature, it will be held to be invalid owing to this violation of the division of powers.
• The corollary to this analysis is that legislation whose pith and substance falls within the jurisdiction of the legislature that enacted it may, at least to a certain extent, affect matters beyond the legislature's jurisdiction without necessarily being unconstitutional. The dominant purpose of the legislation is still decisive.
• Merely incidental effects will not disturb the constitutionality of an otherwise intra vires law.[3]

The pith and substance doctrine is founded on the recognition that it is in practice impossible for a legislature to exercise its jurisdiction over a matter effectively without incidentally affecting matters within the jurisdiction of another level of government.[4]

Also, some matters are by their very nature impossible to categorize under a single head of power: they may have both provincial and federal aspects. The double aspect doctrine, which applies in the course of a pith and substance analysis, ensures that the policies of the elected legislators of both levels of government are respected. The double aspect doctrine recognizes that both Parliament and the provincial legislatures can adopt valid legislation on a single subject depending on the perspective from which the legislation is considered, that is, depending on the various aspects of the matter in question.[5]

In certain circumstances, however, the powers of one level of government must be protected against intrusions, even incidental ones, by the other level. The courts have developed the doctrines of interjurisdictional immunity and federal paramountcy.[6]

The doctrine of interjurisdictional immunity recognizes that the Canadian Constitution is based on an allocation of exclusive powers to both levels of government, not concurrent powers, but the powers are bound to interact. It is a doctrine of limited application that should be restricted to its proper limit.[7]

Interjurisdictional immunity should in general be reserved for situations already covered by precedent. In practice, it is largely reserved for heads of power that deal with federal things, persons, or undertakings, or if, in the past, its application has been considered absolutely indispensable or necessary to achieve the purpose for which exclusive legislative jurisdiction was conferred, as discerned from the constitutional division of powers as a whole, or what is absolutely indispensable or necessary to enable an undertaking to carry out its mandate in what makes it specifically of one jurisdiction or the other.[8]

While in theory, a consideration of interjurisdictional immunity is apt for consideration after the pith and substance analysis, in practice, the absence of prior case law favouring its application to the subject matter at hand will generally justify a court proceeding directly to the consideration of federal paramountcy.[9]

Even if the doctrine of interjurisdictional immunity is properly available, the level of the intrusion on the core of the power of the other level of government must be considered. To trigger the application of the immunity, it is not enough for the provincial legislation simply to affect that which makes a federal subject or object of rights specifically of federal jurisdiction. The difference between "affects" and "impairs" is that the former does not imply any adverse consequence whereas the latter does. In the absence of impairment, interjurisdictional immunity does not apply. It is only if the adverse impact of a law adopted by one level of government increases in severity from affecting to impairing that the core competence of the other level of government or the vital or essential part of an undertaking it duly constitutes is placed in jeopardy.[10]

According to the doctrine of federal paramountcy, if the operational effects of provincial legislation are incompatible with federal legislation, the federal legislation must prevail and the provincial legislation is rendered inoperative to the extent of the incompatibility. The doctrine applies not only to cases in which the provincial legislature has legislated pursuant to its ancillary power to trench on an area of federal jurisdiction, but also to situations in which the provincial legislature acts within its primary powers, and Parliament pursuant to its ancillary powers. To trigger the application of the doctrine, the onus is on the party relying on the doctrine of federal paramountcy to demonstrate that the federal and provincial laws are in fact incompatible by establishing either that it is impossible to comply with both laws or that to apply the provincial law would frustrate the purpose of the federal law.[11]