"The purpose of s. 35(1) of the Constitution Act, 1982 is to facilitate the ultimate reconciliation of prior Aboriginal occupation with de facto Crown sovereignty" (571).
Taku River Tlingit First Nation v. British Columbia (Project Assessment Director),  3 S.C.R. 550
[T]he Court’s reference to de facto Crown sovereignty signals two key points: (1) the Court is questioning, at a minimum, the legitimacy, or the de jure quality, of Crown sovereignty; and (2) the Court intends nonetheless to treat Crown assertions of sovereignty as though they were legally valid, while providing the Crown (including Parliament and provincial legislatures) time and guidance to perfect those assertions" (25).
"Over the quarter century from Sparrow to Tsilhqot’in, the Court has thus steadily ratcheted up the urgency of its calls for the Crown to negotiate treaties where treaties have yet to be concluded — that is, where questions are most pressing about the legitimacy of 'de facto' or 'assumed' Crown sovereignty. Against the background of this case law, then, the primary function of these striking qualifications of Crown sovereignty is to signal to the Crown an urgency to repair the questionable foundations of its sovereign claims, at least where treaties are lacking" (29-30).
Beaton, Ryan. "De Facto and De Jure Crown Sovereignty: Reconciliation and Legitimation at the Supreme Court of Canada." Constitutional Forum constitutionnel, vol. 27, no. 1, 2018, pp. 25-33.