Ottawa's federal carbon tax is an unconstitutional intrusion into provincial jurisdiction.
Stated by: Argued by Alberta in its 2019 reference and by independence advocates
Summary
Alberta did argue this, and its own Court of Appeal initially agreed, but the question was settled the other way. In 2021 the Supreme Court of Canada upheld the Greenhouse Gas Pollution Pricing Act in a 6-3 ruling, finding that setting minimum national standards for carbon pricing is a matter of national concern under the peace, order and good government clause. The Court also held the charges are valid regulatory charges, not unconstitutional taxes. Presenting the federal carbon price as legally unconstitutional contradicts the binding ruling, even though the policy remains politically contested.
Evidence
In Reference re Greenhouse Gas Pollution Pricing Act, 2021 SCC 11, a 6-3 majority held the Act constitutional as a matter of national concern under the POGG clause of the Constitution Act, 1867.
Supreme Court of Canada, References re GGPPA (2021) (opens in a new tab)
Alberta, Saskatchewan and Ontario challenged the law; the Alberta Court of Appeal found it unconstitutional, but the Supreme Court found the federal charges are valid regulatory charges rather than taxes.