At the time of Confederation, the Supreme Court of Canada did not exist. However, the Constitution Act, 1867 stipulated that the federal Parliament may provide for the "Constitution, Maintenance, and Organization of a General Court of Appeal for Canada." In 1875, an act was finally passed to create the Supreme Court.
At the time of its creation, the Supreme Court was not the final court of appeal in Canada; its decisions could be further appealed to the Judicial Committee of the Privy Council in London, UK, for final judgment. Over the years, appeals to the Judicial Committee of the Privy Council were gradually phased out, and the Committee's jurisdiction over Canada finally ended in 1949. Since then, the Supreme Court of Canada has been the highest court of appeal for civil, criminal and constitutional cases.
The Supreme Court Act sets out the fundamental aspects of the Court, such as its composition and the method of appointing its judges. There was considerable discussion about the necessity of Québec representation in the composition of the Supreme Court, in particular because of Québec's civil law system. This led to a protection being added in 1875 to address Québec's concerns.
This protection has been upheld throughout the various reforms to the Act. Presently, the Supreme Court is composed of nine judges, three of whom must come from Québec, either as a judge of the Court of Appeal or the Superior Court of Québec or as a lawyer of at least 10 years' standing with the Barreau du Québec at the time of their appointment (Supreme Court Act, RSC (1985), c. S-26, ss. 4(1), 5 and 6).
The fact that three of the nine seats on the Supreme Court are "reserved for Québec," is a constitutional guarantee that cannot be changed without Québec's consent. This protection serves to "ensur[e] that the Court has civil law expertise and that Quebec's legal traditions and social values are represented on the Court and that Quebec's confidence in the Court be maintained" (Reference re Supreme Court Act, ss. 5 and 6,  1 SCR 433, para. 18).
The authority to appoint judges to the Supreme Court resides with the Governor in Council (Supreme Court Act, s. 4(2)). In concrete terms, this means that, legally speaking, the federal government alone exercises this discretion. Despite what the principle of federalism might entail, there is at present no constitutional requirement to consult the provinces in the Supreme Court appointment process, and this even though the Court is also the final arbiter of disputes regarding the distribution of legislative powers between federal and provincial governments.
Québec has continually demanded changes to the appointment process for Supreme Court judges. It has argued that it should have the constitutional right to participate in the appointment process for the three judges whose seats are reserved for Québec on the Supreme Court and to consent to those appointments. This demand was expressly reiterated in a resolution unanimously adopted by the National Assembly of Québec on October 29, 2013.
When the legality of the appointment of a Federal Court of Appeal judge to one of the seats reserved for Québec on the Supreme Court of Canada was challenged, the federal government asked the Supreme Court, in a reference issued on October 22, 2013, to rule on two questions pertaining to the appointment that was being challenged.
The first question to be addressed was whether or not the prime minister could appoint a former member of the Barreau du Québec to one of the seats reserved for Québec on the Supreme Court of Canada.
The second question to be addressed was whether or not the Parliament of Canada had the authority to legislate the eligibility requirements for the appointment of Supreme Court judges as set out in the Supreme Court Act, either to modify these requirements or to adopt declaratory provisions regarding their interpretation. This second question made express reference to the declaratory provisions regarding sections 5 and 6 of the Supreme Court Act that were tabled before the federal Parliament on the same date that the reference was issued (October 22, 2013) in an omnibus budget bill. Section 5 sets out requirements for appointments to the Supreme Court in general, while section 6 sets out specific requirements for the three seats reserved for Québec.
The declaratory provisions stated that, for greater certainty, a person could be appointed as a Supreme Court judge if they were at any time a member of the bar of a province (for the purposes of section 6, the Barreau du Québec). This implied that a judge of the Federal Court of Appeal who was a former member of the Barreau du Québec could be eligible for appointment to one of the seats reserved for Québec.
Therefore, the Supreme Court had to decide on two separate issues: the interpretation of the eligibility requirements currently in force, and the constitutional jurisdiction to modify them. Several interveners participated in this reference, including the attorneys general of Québec and Ontario.
The Court handed down its opinion on March 21, 2014. A majority of judges (six out of the seven that heard the case) concluded that the appointment of the nominee was void from the beginning, as the nominee did not meet the eligibility requirements for appointment set out in section 6 of the Supreme Court Act, which stipulates that those appointed must be either a judge of the Superior Court of Québec or the Appeal Court of Québec, or a member of the Barreau du Québec at the time of their appointment. It concluded that this interpretation reflected the original will of parliamentarians, dating back to the creation of the Supreme Court in 1875, to provide a special regime for Québec due to its civil law tradition and distinct social values, with the purpose of legitimizing the Court in the eyes of Quebecers.
On the second question, the Court unanimously concluded that Québec's representation on the Supreme Court was protected under section 41 of the Constitution Act, 1982 and that changes to that section required the unanimous consent of both houses of the federal Parliament and all the provincial legislative assemblies, giving Québec the power to dissent to any such changes. A majority of judges also concluded that "any substantive change in relation to [the] eligibility requirements" must be made by unanimous consent (section 41 of the Constitution Act, 1982) and that "the other essential features of the Court" could only be amended using the 7/50 formula (section 42 of the Constitution Act, 1982). The unilateral amendment of section 6 of the Supreme Court Act, tabled before the federal Parliament and finally adopted on December 12, 2013, was therefore deemed unconstitutional.
On May 22, 2019, the Gouvernement du Québec and the federal government reached a landmark administrative agreement concerning the appointment process for the three Supreme Court seats reserved for Québec. Under this agreement, an independent advisory board for Québec would be created and the Gouvernement du Québec would be meaningfully involved in the process leading to the prime minister's recommendation of a nominee.
The agreement was reached in the aftermath of Justice Clément Gascon's retirement and led to the appointment of Justice Nicholas Kasirer. The arrangement applies to all future appointments of Québec judges on the Supreme Court, unless the parties agree to amend the process. The agreement signals a commitment by both governments to furthering discussions about the role that Québec should play in the appointment process for the three Québec seats on the Supreme Court.