The Quebec government has made news, even on this side of the pond, by introducing Bill 4, which purports to amend the Constitution Act, 1867 “by inserting the following section after section 128: ‘128Q.1. Section 128 does not apply to Quebec'”. Section 128 provides, in part, that
Every Member of the Senate or House of Commons of Canada shall before taking his Seat therein take and subscribe before the Governor General or some Person authorized by him, and every Member of a Legislative Council or Legislative Assembly of any Province shall before taking his Seat therein take and subscribe before the Lieutenant Governor of the Province or some Person authorized by him, the Oath of Allegiance contained in the Fifth Schedule to this Act.
No more oath of allegiance to King Charles, then, for members of the National Assembly? Not so fast, say a number of people whose judgment I regard highly. A province (or for that matter Parliament) cannot unilaterally change this provision’s application to itself, though, as Lyle Skinner notes, there seems to be some division of views on what the appropriate procedure would be.
But I’m not sure I see what it is that stops a province from proceeding unilaterally; or at any rate, I have not seen the relevant evidence yet, though I admit I haven’t followed this whole controversy closely. I should also note that I what I am about to say does not endorse Quebec’s predilection for purporting to inscribe amendments to its provincial constitution into the Constitution Act, 1867. I think this way of doing things is self-indulgent and silly, and I don’t know whether it is lawful either. Perhaps Bill 4 could be attacked on this ground, but I leave this question aside and focus on its substance.
The authority for Bill 4, if it exists, must come from section 45 of the Constitution Act, 1982, which provides that “[s]ubject to section 41, the legislature of each province may exclusively make laws amending the constitution of the province.” Legislation must, satisfy two obvious criteria to be valid under this provision: it must be concerned with “the constitution of the province” and it must not trench on matters protected section 41 of the Constitution Act, 1982.
The first test is explained in Justice Beetz’s majority judgment in Ontario (Attorney General) v OPSEU,  2 SCR 2. It has two branches. First,
is the enactment constitutional in nature? In other words, is the enactment in question, by its object, relative to a branch of the government of [the province] or, to use the language of this Court in Attorney General of Quebec v Blaikie,  2 SCR 1016, at p. 1024, does “it [bear] on the operation of an organ of the government of the Province”? Does it for instance determine the composition, powers, authority, privileges and duties of the legislative or of the executive branches or their members? Does it regulate the interrelationship between two or more branches? Or does it set out some principle of government? (38-39)
The existence, contents, and abolition of an oath to be sworn by members of the legislative assembly obvious meets this test, bearing as it does on the composition and duties of the members of the legislative branch. The fact that s 128 lies outside the part of the Constitution Act, 1867 entitled “Provincial Constitutions” is neither here nor there. It is the substance that matters here, as Justice Beetz pointed out.
The second branch of the OPSEU test is the one that those who believe Quebec lacks the authority to enact Bill 4 have in mind. It says that
provisions relating to the constitution of the federal state, considered as a whole, or essential to the implementation of the federal principle, are beyond the reach of the amending power bestowed upon the province … Furthermore, other provisions of the Constitution Act, 1867 could be similarly entrenched and held to be beyond the reach of s. 92(1), not because they were essential to the implementation of the federal principle, but because, for historical reasons, they constituted a fundamental term or condition of the union formed in 1867. (39-40)
Now, I think it’s obvious that the oath of allegiance has nothing to do with the federal principle and the distribution of powers among Parliament and the provincial legislatures, or with “the constitution of the federal state, considered as a whole”. On the contrary, part of the point of Canadian federalism is that Parliament and the provincial legislatures function autonomously. They are elected in separate elections, pursuant to different electoral legislation (and, potentially, with a different franchise, though subject to s 3 of the Canadian Charter of Rights and Freedoms); they have different privileges and different internal procedures.
If the second branch of the OPSEU test prevents provinces from abolishing the oath of allegiance for their legislators, it must be because this oath “constituted a fundamental term or condition of the union formed in 1867”. And… I just have a hard time thinking that that’s the case, whether for reasons of form or substance.
So far as form is concerned, it is true that s 128 mentions federal and provincial legislators in the same provision, indeed in the same sentence. But I don’t think it follows that they cannot be disaggregated. Consider s 96 of the Constitution Act, 1867, which provides in part that “the Governor General shall appoint the Judges of the Superior, District, and County Courts in each Province”. Here too, federal and provincial institutions are mentioned ― and indeed, not merely mentioned in parallel as in s 128, but intertwined. Yet that did not stop the provinces from exercising their s 92(14) power over “the Constitution, Maintenance, and Organization of Provincial Courts” to abolish District and County courts.
As for substance, the example to which Justice Beetz points in OPSEU is s 133 of the Constitution Act, 1867, which imposes the requirement of legislative and judicial bilingualism on both Parliament and the Quebec legislature. This is the provision considered in Blaikie. The Supreme Court referred to the judgment of the Quebec Superior Court “[o]n matters of detail and of history”. (1027) That judgment, for its part, quoted at some length from the Confederation Debates, where John A. Macdonald noted that it “was proposed by the Canadian Government … and it was assented to by the deputation from each province that the use of the French language should form one of the principles upon which the Confederation should be established”. Meanwhile, Georges-Étienne Cartier added that
The members of the [Quebec] Conference had wanted that this [French-Canadian] majority [in Quebec] be unable to enact the abolition of the use of the English language in the local legislature … just as the English majority in the Federal legislature would be able to do it to the French Language.
This is what a fundamental term of confederation looks like. A quick skim through PrimaryDocuments.ca doesn’t suggest any equivalent attention having been paid to the oath of allegiance. It was only a quick skim and it’s entirely possible that I have missed something, of course. But unless and until someone points to specific facts that suggest that the oath had any sort of comparable importance, I will not be persuaded that it was a “fundamental term or condition” without which Confederation would not have happened.
Thus, I don’t think that the OPSEU test prevents a province from changing or abolishing the oath of allegiance the members of its legislature must subscribe. There remains, though, the other restriction on section 45: section 41 and, specifically, the restriction that a province may not amend its constitution so far as it relates to “the office of the Queen, … and the Lieutenant Governor”.
Mr Skinner, in the tweet linked to above, says he “ha[s] not seen anyone suggest” that this restriction applied, but this overlooks obiter dicta in Blaikie. In responding to Quebec’s contention that s 133 was similar to certain other provisions of the Constitution Act, 1867 in being part of the provincial constitution despite not being included in the part entitled “Provincial Constitutions”, the Court had considered s 128. It said, however, that it “raises a different issue, referable to the office of the Governor-General and of the Lieutenant-Governor and touching the position of the Crown in respect of members of the legislative chambers, so long as such chambers exist”. (1024) But the Court did not fully canvass this issue, stating that “[i]t does not seem necessary to come to a determination whether s 128 is part of the Constitution of the Province and amendable as such”. (1025)
For my part, I find it difficult to accept the Court’s suggestion. I do not think that an abolition of the oath of allegiance affects “the office” of the monarch. The highest authority we have on the meaning of this phrase is Motard v Attorney General of Canada, 2019 QCCA 1826, where the Quebec Court of Appeal held that it referred to “the powers, status or constitutional role devolved upon the Queen”.  While I suspect that that judgment was wrong in its key holding ― that the rules of succession to the throne were not also part of the royal “office” ― I do not see the existence or otherwise of the oath as pertaining to “the powers, status or constitutional role” of the sovereign. It is a constraint on members of the legislature, not a privilege or power of the King.
In short, subject to better historical evidence on the importance of the oath of allegiance as a condition of Confederation coming to light, I think that a province has the power to dispense with it unilaterally. That does not make such a dispensation a good idea, though I have argued elsewhere that similar oaths are useless at best and pernicious at worst. It is arguable that legislators are in a different position than would-be citizens or would-be lawyers, but I don’t know how compelling these arguments are. And, of course, even the desirability of abolishing the oath requirement, let alone the constitutionality of doing so, has nothing to do with the desirability of preserving the monarchy. God save the King!