The chief justice of the Supreme Court of Canada voiced concern Thursday about the confusion a New Brunswick man's fight for the right to buy cheap beer in Quebec could leave in its wake.

Beverley McLachlin said if the country's highest court sides with Gerard Comeau's lawyers, deeming interprovincial trade barriers to include tariffs and non-tariff restrictions alike, it would be shifting from a clear law that prohibits customs duties to one where provinces would have to demonstrate any restriction serves a "higher purpose."

McLachlin said there are myriad trade barriers.

"They may be environmental measures, they can be economic measures, they can be health measures — my concern is that we will be introducing a certain area of uncertainty, a lot of litigation, [and] maybe in order to avoid that, imposing a huge burden on governments to come up with some agreements quickly so that our society can be regulated in an orderly fashion," she said.

Other members of the nine-justice panel expressed similar reservations during the second and final day of hearings in Ottawa about the case that could have far-reaching implications for agricultural supply management, the economy and consumer choice.

​The case dates back to 2012, when Comeau, a retired NB Power lineman from Tracadie, was stopped at the New Brunswick-Quebec border by RCMP. He was fined $292.50 for violating the New Brunswick Liquor Control Act by having 14 cases of beer, two bottles of whisky and one bottle of a liqueur.

The act sets a personal importation limit of 12 pints of beer (about 18 cans or bottles), or one bottle of wine or spirits.

Comeau contested the charge and Campbellton provincial court Judge Ronald LeBlanc ruled in April 2016, the liquor restriction was unconstitutional. Section 121 of the Constitution Act states products from any province "shall … be admitted free into each of the other provinces."

Gerard Comeau stayed at home in Tracadie rather than attending the Supreme Court hearing in Ottawa. (Serge Bouchard/Radio-Canada)

New Brunswick's attorney general appealed LeBlanc's decision to the country's highest court, arguing that upholding Comeau's acquittal would "propose an end to Canadian federalism as it was originally conceived, has politically evolved and is judicially confirmed" by the Supreme Court itself, which has previously held Section 121 prohibits only "customs duties."

But since that 1921 decision — in Gold Seal Ltd. v. Alberta — interprovincial trade barriers have "just multiplied," Ian Blue, one of Comeau's lawyers, argued Thursday.

"We've gone way past the point where that's fair," he said, proposing the court adopt a new test, one that's "more restrictive to barriers."

He acknowledged the chief justice's concerns that it could prompt "some initial litigation."

But the provincial officials who put barriers in place are capable of negotiating, he said,

"Yes it'll take extra work, but that's what it might require to comply with the Constitution."

Policy-making power at risk

Justice ​Andromache Karakatsanis suggested adopting the interpretation proposed by Comeau's lawyers would have "a dramatic impact on our Constitutional balance."

Blue took issue with the adjective "dramatic."

"It will be an additional limitation," he said.

Ian Blue, one of Comeau's lawyers, contends the trial judge followed the correct approach in reaching the 'Comeau Interpretation' of Section 121, including an examination of the wording of the provision and its legislative history and context.​ (CBC) Justice Russell Brown questioned taking policy-making power away from elected legislators and handing it to judges, when politicians are accountable to the public.

Blue replied, "People have no voice in the types of negotiations that politicians engage in over trade barriers, but they do have a voice before the cold impartiality of a court of justice."

Justice Malcolm Rowe said it's difficult to conceive of Sir John A. Macdonald and the other Fathers of Confederation "contemplating that courts would sit in judgment on the adequacy of legislative decisions."

A lawyer representing the Montreal Economic Institute, one of the interveners in the case, said it's fortunate the Constitutional method of interpretation doesn't rely solely on original intent.

"We have a living tree that you are charged with tending and interpreting as it continues to grow," said Mark Gelowitz on behalf of the think tank.

It is this court's role to tell us what the Constitution means. It's our job to make it work. - Mark Gelowitz , Montreal Economic Institute

"And that's why in our Constitutional framework, we need judges to make those kinds of decisions, particularly with respect to words that were written 150 years ago in circumstances where the framers could not have contemplated the world we live in," Gelowitz said.

Interpreting the Constitution is the "core jurisdiction" of the court, he said, and it includes "making decisions about whether a legislative purpose falls within Constitutional boundaries, he said.

Mark Gelowitz, on behalf of intervener the Montreal Economic Institute, said the court should not be concerned about whether it might 'cause some trouble' and should not 'pull its punches' in overruling a 1921 decision that has served as precedent. (CBC)

Gelowitz urged the court not to approach the task with reluctance based on whether the correct interpretation of the Constitution "might cause some trouble."

"It is this court's role to tell us what the Constitution means. It's our job to make it work," he said.

"So in my submission the court must not pull its punches in correcting the mistake that was made in Gold Seal simply because it's a mistake that's been relied upon for a very long time."

The court also heard submissions Thursday from 10 other interveners, ranging from small wineries and beer giants, to a marijuana advocacy group and a consumer organization.

On Wednesday, lawyers for New Brunswick, the federal government, seven other provinces and two territories, as well as an intervener group of agriculture supply management associations known jointly as the SM-5 Organizations presented their arguments.

McLachlin announced the court was reserving judgment to an undetermined date, adding she was confident this came as no surprise to anyone.

Decisions are generally delivered within four to six months, but this was McLachlin's last day on the bench before she retires, and it's unclear if or how that might affect the timing.

'Race to the bottom'

If the court upholds Comeau's acquittal, a senior policy analyst for the Canadian Cancer Society warned the result will be a "race to the bottom" for provincial standards protecting the public.

Rob Cunningham, an Ottawa lawyer, says the case has been "mischaracterized" by some as being about allowing beer brewed in one province to be sold in another — the so-called "free the beer" case.

He contends the case could have "serious implications" for the ability of provincial governments to adopt legislation for products such as alcohol, tobacco and marijuana, including controlling their retail distribution.

Rob Cunningham, of the Canadian Cancer Society, says the trial judge's interpretation of the Constitution Act would mean provinces could adopt health, safety, environmental, taxation and other measures regarding products manufactured within their own province, but those measures would not apply to products manufactured in other provinces. (Submitted by the Canadian Cancer Society)

Cunningham, who attended the Supreme Court hearing, supports New Brunswick's position that provinces should have the ability to regulate harmful substances such as alcohol.

Otherwise, there would be "widespread alcohol smuggling," with lower prices leading to increased consumption, he said.

If LeBlanc's ruling is allowed to stand, it would also "provide a mechanism for companies to get around provincial (and municipal) health, safety, environment and other legislation," Cunningham states in a legal commentary, titled R v Comeau: Reflections from the Perspective of Health.

"A single province with a weak standard could have products manufactured and exported to other provinces," says the paper published on the Canadian Legal Information Institute's website.

It could also open the door to legal challenges, such as tobacco companies seeking to overturn provincial bans on menthol cigarettes, and pesticide companies trying to overturn provincial bans on the cosmetic use of pesticides, suggests Cunningham, whose paper is cited in written submissions to the court from New Brunswick, Newfoundland and Labrador and Nunavut.

Interpreting the 'Fathers'

But even if Cunningham's predictions proved true, the provinces and territories could mitigate "each and every one through true co-operative federalism," Comeau's lawyers contend.

"Concern about such work does not absolve provincial officials from their duty to uphold the Constitution, nor does it allow them to argue against its proper interpretation in order to serve their parochial interests," Blue, Daria Peregoudova, Arnold Schwisberg and Mikael Bernard argue in their reply factum.

The lawyers assert the Fathers of Confederation intended to allow the free movement of items between provinces, unrestrained by any barriers, whether they be tariffs or non-tariff restrictions that make importing and exporting products difficult or costly.