TORONTO -- Ontario's top court will release its ruling on the constitutionality of the federal carbon tax on Friday.
The Court of Appeal heard arguments over four days in April after the Progressive Conservative government challenged the levy, arguing it allows Ottawa to step into areas of provincial authority, undermining co-operative federalism.
The court case is just one of the ways in which the Ontario government has gone after the tax.
It is also mandating anti-carbon tax stickers be displayed on gas pumps, it has taken out radio and TV ads slamming the tax, and it has co-ordinated caucus social media posts speaking out against it.
Other provinces have launched similar challenges against the federal tax, and Saskatchewan is appealing to the Supreme Court of Canada after losing its court challenge last month.
Saskatchewan's Court of Appeal found that establishing minimum national standards for a price on greenhouse gas emissions falls under federal jurisdiction.
The federal tax has been imposed on provinces that have not implemented their own carbon levies: Ontario, New Brunswick, Saskatchewan and Manitoba. All but New Brunswick have gone to court over it.
Alberta has also filed a reference case with its Court of Appeal, asking for a legal opinion on the constitutionality of the carbon tax.
The levy takes effect in Alberta on Jan. 1, 2020. Alberta passed legislation earlier this month that repealed its provincial carbon tax and fulfilled a promise United Conservative Premier Jason Kenney made before the April election in that province.
Premier Doug Ford has said that if carbon tax opponents lose in the courts, they will win at the ballot box in October. Federal Conservative Leader Andrew Scheer has promised to scrap the carbon tax if he is elected as the next prime minister.
The tax is expected cost to a typical household $258 this year and $648 by 2022.
The federal government is providing rebates and had estimated the average rebate would be $300 in Ontario, but the Canada Revenue Agency said earlier this month the average payment was $203 in the province.
