Provincial power plays: B.C. and Alberta test the boundaries in pipeline debate

At the heart of the cooling dispute between Alberta and B.C. were two provinces flexing their muscles, testing the limits of their powers.

Premiers Rachel Notley and John Horgan have both said they're working in the interests of the citizens they represent. But it's open to interpretation whether Alberta hadthe right to ban B.C. wine or if B.C. has the authority to restrict bitumen exports from the federally approved Trans Mountain pipeline.

Those are questions for the court, and both provinces have strong arguments to make, a pair of UBC professors told CBC News.

And that's exactly where the bitumen question is headed. Horgan said Thursday that British Columbia will be consulting its lawyers on a legal challenge that will determine the province's constitutional rights around regulating shipments from the pipeline.

There is plenty of precedent on this question, according to law professor Jocelyn Stacey.

"We have lots of cases that then deal with what happens if a conflict arises between a constitutionally valid provincial measure and a federal undertaking like a pipeline," Stacey said.

Canadian provinces have broad authority to enact environmental regulations, she explained, but that doesn't necessarily mean those regulations apply to projects under federal jurisdiction.

And if a provincial regulation somehow impairs or frustrates the activities of the federal government, it would likely be quashed by the courts, Stacey said.

Precedent-setting cases

She pointed to a pair of decisions from the Supreme Court of Canada that should give the province some guidance.

The first dates back to 1995, when the Ontario government objected to controlled burning that Canadian Pacific was doing along its railways.

"The Supreme Court found that Ontario's provincial environmental regulations still applied to those burning practices. Even though the railway in this case was a federal undertaking, it still had to comply with provincial law," Stacey explained.

More recently, however, the same court ruled against the Quebec town of Chteauguay after its local government tried to block construction of a new cellphone tower, arguing that it threatened the health of local residents.

In that 2016 case, the court found that municipal governments do not have the power to decide where towers can be built.

Without knowing the exact regulations that the B.C. government plans to test, Stacey couldn't speculate on the final outcome, but she'll be watching closely.

"Everybody here is seeking clarity around these constitutional issues," she said.

'Alcohol stands aside'

On the other hand, it could be a long time before we get an official answer on the legality of the wine ban, now that Notley has dropped her province's boycott.

The B.C. government had plans to contest it under the Canadian Free Trade Agreement (CFTA) and the B.C. Wine Institute was preparing to file a constitutional challenge in court.

According to economics professor Werner Antweiler, there's a very real chance both bodies would have upheld the ban.

That's because the rules for trading alcohol between provinces are much different than those for just about any other product.

"This is actually one of the areas that are not well covered yet by internal free trade agreements between the provinces," Antweiler said.

Every province in the country has the jurisdiction to enact strict rules for managing its liquor supply,he explained.

"As a result, alcohol stands aside. All other goods, really, are now covered under the CFTA," he said.

Claims from the wine institute's president that "any other product from any other province" could be open to similar interprovincial bans are overblown, Antweiler explained.

But he added that it's possible when recreational marijuana becomes legal, it could also be used as a bargaining chip between provinces, because the plan is to regulate it in much the same way as booze.