What does the Incidental Effects Doctrine help to determine in legislative law?

The Incidental Effects Doctrine is a principle used to analyze the pith and substance of legislation by looking at its dominant feature or main objective. This doctrine is particularly useful in situations where a law may have effects or implications that extend beyond its primary goal or intention. By focusing on the dominant feature of the law, courts can ascertain whether it falls within the jurisdiction of the federal or provincial government as defined by the Constitution.

This approach allows for a nuanced understanding of legislative intent and ensures that laws can be evaluated based on their underlying purpose rather than just their incidental impacts. Therefore, in the context of determining the essence and jurisdiction of a law, the Incidental Effects Doctrine serves to clarify and establish what constitutes the core objective or dominant feature of the legislation, which is crucial for matters of constitutional law in Canada.