Interveners line up on both sides of debate

But Saskatchewan argues a federally imposed carbon tax is “constitutionally illegitimate” because it only applies to some provinces.

“Under our Constitution the federal government has no authority to second-guess provincial decisions with respect to matters within provincial jurisdiction,” court documents filed by the province say.

It also cites part of a 2017 legal opinion released by Manitoba, which last year pulled out of the federal plan. Legal expert Bryan Schwartz concluded that there’s a strong chance the Supreme Court of Canada would uphold a federal carbon tax.

But the law professor from the University of Manitoba said a “credible” yet “untested” argument could be made about how such a measure is applied. Schwartz wrote that a case could be made that Ottawa would be “arbitrarily denying” Manitoba authority to deal with emissions reductions in its own way.

Ottawa argues climate change is a national concern and the federal government’s power to impose a carbon tax comes from Section 91 of the Constitution, which states laws can be made “for the peace, order and good government of Canada.”

Adams said that branch of jurisdiction is not often cited in constitutional disputes because it’s difficult for courts to define the limits of a “national concern.”

Arguments are to be heard before a panel of five judges. There are also submissions from 16 interveners representing both sides of the dispute.

Applicants in support of Canada’s position include the government of British Columbia, The David Suzuki Foundation and the Athabasca Chipewyan First Nation.

Amir Attaran, lawyer for the northern Alberta First Nation, argues a federal carbon price is “a constitutional necessity” because the effects of climate change have an impact on northern Indigenous peoples’ rights to hunt, fish and trap.

Interveners on Saskatchewan’s side include anti-carbon-tax allies such as Alberta’s United Conservative Party and the government of Ontario, which has filed its own legal challenge.

Todd Lewis, president of the Agricultural Producers Association of Saskatchewan, which also has intervener status, said he supports the province’s position because he feels a carbon tax would disproportionately affect farmers.

Adams said it’s inevitable the dispute will not be settled in Saskatchewan’s highest court and will ultimately be decided by the Supreme Court.

“I think everybody understands that we are not in Game 7 of the Stanley Cup final yet. We’re in a preliminary round of the playoffs.”