On Feb. 28, the Supreme Court of Canada rendered a landmark judgment in the case of Nevsun Resources Ltd. v. Araya. This case raised a largely unexplored question in Canadian law: whether plaintiffs can bring civil claims in Canada for human rights violations committed abroad. As Justice Rosalie Abella wrote in the opening of her majority judgment, this appeal involved “the application of modern international human rights law, the phoenix that rose from the ashes of World War II and declared global war on human rights abuses.”

And the facts of the case are indeed grisly. The plaintiffs, refugees from Eritrea, claimed that Nevsun Resources, a Canadian mining company based in British Columbia, had been complicit in breaches of international human rights law—including forced labor, slavery, and torture, by the Eritrean government...

In its appeal, Nevsun argued that the plaintiffs’ claims should be struck without consideration of the merits, on the basis that (a) the act of state doctrine applied, such that Canadian courts lacked subject-matter jurisdiction over any of the plaintiffs’ claims, and (b) there existed no separate cause of action in Canadian tort law for breaches of customary international law.

In a closely divided decision, the Supreme Court dismissed Nevsun’s appeal. Formally, this allowed the plaintiffs’ claims to proceed on the basis that Nevsun had not met the standard for a motion to strike by showing that it was “plain and obvious” that the claims could not succeed...

The majority and dissenting opinions agreed that through the doctrine of adoption, customary international law is automatically incorporated into Canadian law in the absence of conflicting legislation...Similarly, the majority and the dissenting opinions agreed that certain norms of customary international law “prohibit conduct regardless of whether the perpetrator is a state.”