Doctrine of Paramountcy
Canada Post Corporation v. Hamilton (City), 2016 ONCA 767 (CanLII)
[42] Once the matter of the challenged legislation is ascertained, the next step is to determine whether the matter comes within one of the heads of power allocated to the enacting legislative body by s. 91 or s. 92 of the Constitution Act, 1867. If not, the legislation is ultra vires and void.
[43] Legislation will not be ultra vires, however, simply because its subject matter, for another purpose, could have fallen under the jurisdiction of the other level of government under a different head of power. The double aspect doctrine provides that “subjects which in one aspect and for one purpose fall within sect. 92, may in another aspect and for another purpose fall within sect. 91”: Hodge v. The Queen (1883), 9 A.C. 117, at p. 130 (P.C.). Accordingly, the doctrine contemplates that some subjects will fall equally under two distinct heads of power, one federal and one provincial: Rogers Communications Inc. v. Châteauguay (City), 2016 SCC 23, 397 D.L.R. (4th) 611, at para. 50.
[44] This double aspect raises the possibility of conflict between valid federal and provincial laws that both deal with the same subject matter. The doctrine of paramountcy stipulates that such conflict is to be resolved in favour of federal legislation: Canadian Western Bank, at para. 32. Where there is a conflict, federal legislation is paramount and the conflicting provincial legislation is inoperative to the extent of the conflict.
[45] The Supreme Court has recently clarified its jurisprudence on what is required for a conflict: Alberta (Attorney General) v. Moloney, 2015 SCC 51, (2015) 3 S.C.R. 327, at paras. 17-29. It summarized when a conflict will occur, at para. 29:
- [I]f the operation of the provincial law has the effect of making it impossible to comply with the federal law, or if it is technically possible to comply with both laws, but the operation of the provincial law still has the effect of frustrating Parliament’s purpose, there is a conflict.
