EDMONTON -- Legal experts say rulings from provincial Appeal Courts on the federal carbon tax aren't about the tax itself, but rather the government's legal grounds for it.

The Alberta Court ruled on Monday that the tax is unconstitutional, but Ontario and Saskatchewan backed the levy in decisions last year.

University of Alberta law professor Eric Adams says the judgments differ because each court understood differently what the law is trying to do.

He says the Alberta judges took its goal to be regulating greenhouse gases overall - a much broader goal - rather than just setting a national price on carbon.

Professor David Wright at the University of Calgary says the tax law relies on a little-used section of the Constitution that judges are now grappling with.

Both agree that Ottawa has plenty of other ways to bring in a carbon tax if the Supreme Court rules against it.

This report by The Canadian Press was first published Feb. 25, 2020