Treaty failure or treaty constitutionalism? The problematic validity of the James Bay and Northern Quebec Agreement

In 1975, the signatories to the James Bay Northern Quebec Agreement (JBNQA) anticipated the possibility that critical portions of the Agreement could be judicially invalidated on federalism grounds. In light of that possibility, the signatories set out their obligations to each other should that invalidation occur. My question is: given all of the constitutional and jurisprudential changes that have happened since, is the JBNQA constitutionally valid today? It certainly is presumed to be valid, but this presumption has never been directly posed to the Supreme Court of Canada. This article builds an argument that the premises established in contemporary jurisprudence, on the law as it now stands, lead to the conclusion that the JBNQA is invalid. While my answer is that current jurisprudence is consistent with the JBNQA's invalidity on federalism grounds, I briefly engage the further question of whether a 'living tree' textual reinterpretation of section 35(1) of the Constitution Act, 1982 could uphold the Agreement's constitutionality despite its federalism defect. In other words, can section 35(1) bear the weight of a treaty amendment clause? I argue that it currently does not but that it could. I then show how such a reinterpretation of section 35(1) would in effect be a reinterpretation of the whole Canadian constitutional order. What is at stake in this discussion of the JBNQA and the Canadian Constitution is nothing less than what the Canadian Constitution is all about.