History
Constitutional Courts and Federal-Provincial Jurisdictional Disputes
Quick fact
In Canada, the Supreme Court has used the 'pith and substance' doctrine to strike down provincial laws that encroach on federal powers—like when a provincial law attempted to regulate aeronautics, which is a federal responsibility.
Why this is interesting
Who settles the fight when a province and the national government both claim the right to make a law? In most countries, it's not a politician—it's a panel of judges.
Read the full explanation
Understanding Constitutional Courts and Federal-Provincial Jurisdictional Disputes
Imagine two parents arguing over who gets to decide what the child eats. In a federation, the 'child' is the public, and the 'parents' are the national and provincial governments. The constitution is the family rulebook that lists who gets to decide what. But rulebooks aren't always clear, and sometimes both parents think they have the right to decide. That's when they go to a referee—the constitutional court. The court reads the constitution, looks at the actual subject of the disputed law, and decides which level of government has the authority. This keeps the federation from breaking apart.
A deeper explanation
Constitutional courts resolve jurisdictional disputes by interpreting the division of powers. The key tool is the 'pith and substance' test, which asks what the true purpose and effect of the law is. If a provincial law is really about a federal matter—like banking or national defense—the court will strike it down. Another principle is 'federal paramountcy': when both levels pass valid laws on the same subject, the federal law prevails. Courts also use 'interjurisdictional immunity' to protect core federal interests from provincial regulation. These mechanisms prevent jurisdictional creep and preserve the balance intended by the constitution.