Supreme Court Hears Appeals on Joinder in the Context of Co-Existing Aboriginal Title Assertions and Treaty Rights

On December 8 and 9, 2025, the Supreme Court of Canada heard two appeals concerning whether non-party Indigenous groups with treaty rights and Aboriginal title assertions should be joined to the Gitanyow Nation’s Aboriginal title action. The Métis Nation of Ontario participated as an intervener.

The first appeal was Nisg̱a’a Nation, as represented by the Nisg̱a’a Lisims Government v. Malii, also known as Glen Williams, et al., in which the Court considered the Nisg̱a’a Nation’s request to be added as a defendant to the Gitanyow Nation’s action based on the provisions of their modern-day treaty – the Nisg̱a’a Final Agreement.

The second appeal was Skii km Lax Ha, also known as Darlene Simpson, also known as Chief Simpson, on behalf of herself and, in her capacity as Tsetsaut/Skii km Lax Ha Hereditary Chief, et al. v. Malii, also known as Glen Williams, et al., concerning the Tsetsaut/Skii km Lax Ha Nation’s request be added as a defendant to the Gitanyow Nation’s action and for leave to file a third-party claim to advance its own Aboriginal title claim to portions of the territory claimed by the Gitanyow Nation.

Both matters were heard before Chief Justice Wagner and Justices Karakatsanis, Côté, Rowe, Martin, Kasirer, Jamal, O’Bonsawin and Moreau. The Court reserved its decision to a later date.

Aird & Berlis LLP acted as counsel to the Métis Nation of Ontario with a team including Jason Madden, Alexandria Winterburn and Alex DeParde (Indigenous Practice Group).