Although the Supreme Court of Canada's decision in Vavilov1 established a general framework for selecting which standard to apply on judicial review, it left open which standard of review applies to reviewing the vires of subordinate legislation, including regulations and guidelines. Vavilov therefore generated lingering uncertainty about whether pre-Vavilov principles still applied in such cases. The SCC had established in Katz Group2 that a regulation would only be struck down if irrelevant, extraneous, or completely unrelated to the enabling statute. In companion decisions, Auer v. Auer, 2024 SCC 36 (Auer); TransAlta Generation Partnership v. Alberta, 2024 SCC 37 (TransAlta), the SCC resolved this uncertainty, holding that the slightly less onerous reasonableness standard is the presumptive standard for reviewing the vires of regulations. Therefore, some regulations on the margins, which may not have been struck down in the past, may be more vulnerable moving forward.
Background
These companion cases emerged from challenges to two distinct sets of regulations. Auer involved a challenge to the Child Support Guidelines,3 which determine the amount of child support one parent must pay to the other. TransAlta involved a challenge to the 2017 Linear Guidelines,4 where TransAlta argued that Alberta's Minister of Municipal Affairs exceeded their authority5 by enacting the Linear Guidelines that (1) violate the common law rule against administrative discrimination, which arises when regulations apply unequally to the actors engaging in the regulated activity, and (2) are inconsistent with the enabling statute.
In both cases, the Court of Appeal...
