The Supreme Court of Canada will issue a ruling today on whether Canadians have a constitutional right to buy and transport alcohol across provincial borders without impediments.

The so-called 'free-the-beer' case also could have major implications for sales of tobacco and cannabis, and for the supply management system relied upon by Canada's dairy and egg industries to maintain prices.

The man at the heart of the case is Gerard Comeau, a retired New Brunswick man who, two or three times a year, drives from his home in Tracadie — some 160 kilometres north of Moncton — to Quebec, where it's cheaper to buy beer and liquor.

In 2012 he was stopped at the New Brunswick-Quebec border by the RCMP and fined $292.50 for having 14 cases of beer, two bottles of whisky and one bottle of liqueur in his vehicle.

You can order a gun from another province and have it delivered to you, but you can't order a bottle of wine. - Dan Paszkowski, president of the Canadian Vintners Association

Most provinces limit how much alcohol people can bring across provincial borders. New Brunswick's Liquor Control Act sets a limit of 12 pints of beer (about 18 cans or bottles), or one bottle of wine or spirits.

"I'm expecting that the Supreme Court is going to give a decision that's going to be fair for everybody. I can't see them saying the province has the right to limit what's coming into the province from another province," said Comeau in an interview with CBC News.

Comeau's argument centres on section 121 of the Constitution Act, which states products from any province "shall ... be admitted free into each of the other provinces."

A 1921 Supreme Court decision interpreted that to mean the products only had to be free from tariffs, not from other barriers such as limits on quantity.

Comeau and others argue that decision offered too narrow an interpretation, and that it led to the proliferation of interprovincial trade barriers.

Gerard Comeau stayed at home in Tracadie, N.B. instead of attending the Supreme Court hearing in Ottawa. (Serge Bouchard/Radio-Canada)

Guns versus wine

One of the 24 intervenors in the case was the Canadian Vintners Association, which has been lobbying for direct-to-consumer wine sales for more than a decade.

"It really is strange that in 2018 you can order a gun from another province and have it delivered to you, but you can't order a bottle of wine," said Dan Paszkowski, president of the Canadian Vintners Association.

"We are one of the only countries in the world that doesn't allow wine to be shipped across provincial borders or state borders."

The number of intervenors in the case is a clear indication of how far-reaching the implications of this case could be. They go far beyond Canadians simply looking to save some money on booze, or to order a hard-to-find Canadian wine.

Provinces — especially those with liquor control boards that operate as alcohol monopolies — rely on alcohol sales for revenue and taxes.

If the Supreme Court rules they can no longer limit imports from provinces with lower prices and taxes, those higher-priced provinces could suffer budget gaps.

Provinces also place limits on the amount of tobacco products Canadians can transport across borders; similar limits could be placed on recreational cannabis when it's made legal for sale. And since the supply management system places limits on both the production and price of certain agricultural commodities, it's at risk as well.

"Especially for the governments, financially, there is a lot at stake," said Comeau's lawyer Mikael Bernard in an interview with CBC News.

High prices a key deterrent

But others say Canadians' health is also at stake.

Canadian Cancer Society senior policy analyst Rob Cunningham argues higher prices on alcohol and tobacco deter consumption — and that's a good thing.

"Provinces should be able to tax harmful products to discourage consumption. We know higher prices have an impact, especially among teenagers," he said.

But Bernard argues the court should concern itself only with interpreting the Constitution, not the potential "aftermath" of its decision.

"Win, lose or draw, I believe that Mr. Comeau can at least be proud that he opened up a nationwide discussion about the issue," he said.

For his part, Comeau said he was never aiming to make legal history. He just wants an answer from the court, either way.

"My aim is to find out whether I can shop wherever I want."