Ontario appealed from the Court of Appeal's decision concerning the Robinson Treaties of 1850, which contained an Augmentation Clause providing for periodic increases to annual payments to the Anishinaabe of Lake Huron and Lake Superior contingent on economic conditions.
The annuities had been frozen at $4 per person since 1875.
The Supreme Court of Canada held that treaty interpretation is reviewable on a correctness standard, and adopted the fourth interpretation of the Augmentation Clause: the annuity is a single payment to the 'Chiefs and their Tribes', with mandatory increases to $4 per person where economic conditions permit, and discretionary increases beyond $4.
The Crown's discretion is not unfettered; it must be exercised diligently, honourably, liberally, and justly, consistently with the honour of the Crown.
No specific fiduciary duties arose in respect of the Augmentation Clause, but the duty of diligent implementation did.
The breach of treaty claims were not statute-barred.
The appeals were allowed in part, cross-appeals dismissed, and a declaration issued directing the Crown to engage in time-bound negotiations with the Superior plaintiffs regarding compensation for past breaches.