The Supreme Court of Canada did much more than strike down three prostitution laws on Friday. It set down a major change to the way lower courts can revisit precedents by the Supreme Court. In doing so, it gave hope to those who support a right to assisted suicide that the Supreme Court will reverse its own 1993 rejection of that right.

Trial judges can overturn previous constitutional rulings in certain circumstances, the court said. And the circumstances in the prostitution ruling were similar to those in a right-to-die case that has worked its way through British Columbia's courts to the Supreme Court.

If new legal issues are raised, or if there is a change in the circumstances or evidence that "fundamentally shifts the parameters of the debate," trial judges may revisit constitutional precedents, Chief Justice Beverley McLachlin wrote. And the trial judge's findings of changes in social norms will carry great weight with higher courts.

Story continues below advertisement

That is what happened in the assisted-suicide cases of Gloria Taylor and Kathleen Carter in B.C. Ms. Taylor, 64, suffered from amyotrophic lateral sclerosis (ALS), and Ms. Carter, 89, from spinal stenosis, a degenerative condition. (Both are now dead.) A trial judge found that changing social norms had shifted the debate, and struck down the crime of assisted in a suicide. But the B.C. Court of Appeal said the judge should have followed the Supreme Court's precedent from 1993, in the Sue Rodriguez case. Ms. Rodriguez, too, had ALS and sought a physician's help to die.

The Supreme Court has always had the power to overturn its own precedents. But Vancouver lawyer Joe Arvay says the court's prostitution ruling suggests a greater likelihood that the court will reject its 1993 thinking about assisted suicide because "of the court's comments on the role of precedent, the importance of deference to the fact finding by the trial judge and its development of the jurisprudence under Section 7 of the Charter."

Traditionally, when the Supreme Court rules on a constitutional issue, only it can overturn the precedent. But Justice Susan Himel of the Ontario Superior Court refused to abide by the Supreme Court's ruling in the 1990 prostitution reference case. In that case, the court upheld laws against brothels and street solicitation. Justice Himel said the arguments were different this time around and there was greater understanding about how laws exacerbate the dangers of prostitution. She amassed 25,000 pages of evidence about those dangers, which the Ontario Court of Appeal said it was entitled to disregard.

The Supreme Court mostly agreed with Justice Himel.

"This balances the need for finality and stability with the recognition that when an appropriate case arises for revisiting precedent, a lower court must be able to perform its full role," Chief Justice McLachlin wrote.

In effect, says Cheryl Milne, executive director of the David Asper Centre for Constitutional Rights, which intervened in the case to argue for the new approach, there is a "planned obsolescence" built into Canadian constitutional law. It does not need to be stuck in the 1980s, when many major constitutional decisions were written, added Sonia Lawrence, a professor at Osgoode Hall Law School.