Interjurisdictional immunity

In Canadian Constitutional law, interjurisdictional immunity is the legal doctrine that determines which legislation arising from one level of jurisdiction may be applicable to matters covered at another level. Interjurisdictional immunity is an exception to the pith and substance doctrine, as it stipulates that there is a core to each federal subject matter that cannot be reached by provincial laws. While a provincial law that imposes a tax on banks may be ruled intra vires, as it is not within the protected core of banking, a provincial law that limits the rights of creditors to enforce their debts would strike at such a core and be ruled inapplicable.

The paramountcy doctrine states that if two pieces of legislation meet, regulate the same activities, and conflict, the federal legislation is paramount, prevails and renders the provincial legislation inoperative. In contrast, the interjurisdictional immunity doctrine is activated even if there is no meeting of legislation or contradiction between federal and provincial statutes. It requires only for the provincial legislation to impact federal things, persons or undertakings significantly. The doctrine renders inapplicable legislation of general application which affects the rights and obligations, impacts the status, or regulates the essential parts of:

exclusively within the core of the jurisdiction of the other order of government.

The doctrine was first formulated to deal with the effects that provincial laws could have on federally incorporated companies.

Until 1966, undertakings which came within federal jurisdiction were held to be immune from otherwise valid provincial laws only if the laws had the effect of sterilizing, paralyzing or impairing the federally authorized activity. However, the scope of the doctrine was expanded in Bell Canada (1966), where a provincial law prescribing a minimum wage was held not to apply in 1966 when it was determined that a valid law could not apply, as such a law “affects a vital part of the management and operation of the undertaking”. It did not matter that no sterilization, paralysis or impairment had occurred.

This doctrine was affirmed in 1988 when the Supreme Court of Canada ruled in three cases that provincial occupational health and safety laws were held to be inapplicable to three federal undertakings engaged in interprovincial transportation and communication. In Bell Canada v Quebec (1988), Beetz J declared:

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