In response to this more classical approach to settling matters of constitutional law, the necessary degree of infringement was revisited in
Canadian Western Bank in 2007, where the Supreme Court of Canada ruled that, in the absence of outright impairment of the "vital or essential part", interjurisdictional immunity would not apply. This was subsequently affirmed in
Lafarge. Therefore, in order to render statutes inapplicable, the impacts that engage the interjurisdictional immunity doctrine must be significant. The requirement is that legislation significantly embrace things, undertakings or persons exclusively in the jurisdiction of the other order of government. The interjurisdictional immunity doctrine will not render inapplicable insignificant impacts caused by legislation of general application. Additionally, though the doctrine was textually justified in
Canadian Western Bank, the court also expressed a preference for relying on the doctrine of federal
paramountcy over interjurisdictional immunity when attempting to resolve federalism disputes (after the impugned legislation had been found valid): While most jurisprudence has revolved around the applicability of provincial laws on undertakings under federal jurisdiction, one must not ignore its relevance with respect to things and persons. For example: :* in the matter of
Canadian maritime law, provincial laws relating to damages, negligence and apportionment have been held not to apply to fill in any gaps that may exist, as maritime law is at the core of the federal power over "Navigation and Shipping". :* certain provincial laws regulating hunting have been held not to apply to
Indians where they significantly interfere with
treaty rights, as such rights have been held to be at the core of the federal power over "Indians and Indian lands". In
Quebec (Attorney General) v. Canadian Owners and Pilots Association ("
COPA"),
McLachlin CJ outlined a two-step test that must be undertaken to determine if interjurisdictional immunity comes into play: • Does the provincial law trench on the protected "core" of a federal competence? • Is the provincial law's effect on the exercise of the protected federal power sufficiently serious to invoke the doctrine of interjurisdictional immunity? Though there remains some debate, it has generally been accepted that the doctrine applies to both the federal and provincial governments equally. Nevertheless, virtually all of the case law concerns situations where provincial laws encroach on federal matters. The Supreme Court has expressed caution in employing the doctrine in future cases because: • It is in tension with the dominant approach that permits concurrent federal and provincial legislation with respect to a matter. • It is in tension with the emergent practice of cooperative federalism. • It may overshoot the federal or provincial power in which it is grounded and create legislative "no go" zones where neither level of government regulates. As McLachlin CJ explained in
Canada (AG) v PHS Community Services Society: ==See also==