Constitutional amendment with provincial consent is not required for electoral reform.
The federal government’s pursuit of electoral reform has raised a number of questions: is reform necessary or desirable at all? If so, what new electoral system to adopt? Should the people be consulted before reform is implemented? And now, thanks to op-eds published by Michael Pal in The Globe and Mail, and Yaakov and Jonathan Roth in The Toronto Star, we also have to ask ourselves whether it would be constitutional. In my view, however, the answer to the latter question is much clearer than to the others. The constitution is no obstacle to Parliament acting alone to implement (most forms of) electoral reform. (By the way, in case you think that my opinion on this is relevant to assessing the argument that follows: I think that electoral reform is a bad idea, and I think that if the government insists on endorsing it, there should be a referendum before reform is implemented.)
Section 44 of the Constitution Act, 1982 ― which prof. Pal describes as an “obscure provision,” and Messrs. Roth do not mention at all ― provides that “exclusively make laws amending the Constitution of Canada in relation to the executive government of Canada or the Senate and House of Commons, subject to sections 41 and 42. As a starting point, it would seem logical to consider electoral reform an amendment to “the Constitution of Canada in relation to … the House of Commons,” and thus within the purview of Parliament, except insofar as sections 41 and 42, to which I will return, provide otherwise.
Those who think unilateral electoral reform would be unconstitutional point to the Supreme Court’s opinion in Reference re Senate Reform, 2014 SCC 32,  1 S.C.R. 704, which introduced the notion of “constitutional architecture” that limits Parliament’s amending power under section 44. The “architecture,” which seems to consist of “assumptions that underlie the text [of the constitution] and the manner in which the constitutional provisions are intended to interact with one another,” is an entrenched part of the constitution, and cannot be amended by Parliament acting alone.
Prof. Pal suggests that the first-past-the-post electoral system is part of that architecture since, although it “is not mentioned directly in the Constitution, … [n]umerous parts of the Constitution presume that [it] is in place.” Moreover, in his view, electoral reform “would affect provincial interests,” although “[l]esser changes than a move to proportional representation could be interpreted as” doing so “only trivially … and not really changing the constitutional architecture.” For their part, Messrs. Roth insist that the Constitution Act, 1867 “expressly assigned to each province a fixed number of ‘electoral districts,’ each entitled to return ‘one member’ to the House. This ‘constitutional architecture’ plainly presupposes district-based elections.” They also point to the use of first-past-the-post in the United Kingdom, to whose constitution ours was intended, according to its preamble, to be “similar in principle.”
But it is not enough, it seems to me, to say that first-past-the-post is how we always elected representatives to show that it is a part of the “constitutional architecture” as the Supreme Court understood that notion in the Senate Reform Reference. In that opinion, the Court said that “the institutions provided for in the Constitution” ― such as the House of Commons ― “can be … changed to some extent under ss. 44 and 45, provided that their fundamental nature and role remain intact.”  That, in my view, is what electoral reform would do. It might change the House of Commons to some extent (though to what extent would depend on the shape the reform takes), but would not affect its “nature” as the representative part of our national legislature or its role of serving as the electoral college for the choice of a Prime Minister, making laws, and pretending to hold government to account.
Prof. Pal never says, unfortunately, what parts of the constitution rely on first-past-the-post, and for my part, I am unable to figure out what they are. It is noteworthy, for instance, that section 3 of the Canadian Charter of Rights and Freedoms provides that “[e]very citizen of Canada has the right to vote in an election of members of the House of Commons” (emphasis mine), as opposed to, say, “the election of a member.” The latter formulation would presuppose election in single-member districts. The former does not, since an election under a system of proportional representation is still “an elections of members of the House of Commons.” As for the provisions assigning a specified number of districts to each province, which Messrs. Roth invoke, these were obviously intended to be, and have been, amended by Parliament acting alone since 1867, as the number of districts and members of Parliament was increased.
Note, by the way, that contrary to what Messrs. Roth say, one or two of the districts created by section 40 of the Constitution Act, 1867 were actually entitled to two representatives in the House of Commons. Indeed, multi-member districts were common in the United Kingdom in 1867 ― most English Members of Parliament represented counties or boroughs that returned two members each, and some counties had three representatives. There were even exceptions to the principle of geographical representation (as well as the one man, one vote principle), in the shape of university constituencies that allowed the holders of some degrees from some universities to elect additional representatives for their almae matres. Quite apart from the fact that the legal effect of the preamble to the Constitution Act, 1867 is matter of doubt on which the Supreme Court has wavered over the years, the claim that geographical constituencies electing single members of Parliament using a first-past-the-post system was a matter of long-standing fundamental constitutional principle in the United Kingdom in 1867 is historically inaccurate.
Thus I am not at all persuaded that the constitution’s entrenched text in any way depends on or implies the first-past-the-post voting system. If anything, I suspect ― though I have not done the historical research to prove it ― that section 3 of the Charter might have been written specifically to avoid entrenching this arrangement. Nor do I think that electoral reform would impermissibly affect the constitution’s architecture. While changes in the relationship between Parliament and the executive are conceivable in the wake of a move to some form of proportional representation, they are unlikely to be fundamental in nature. As for changes to the relationship between Parliament and the provinces, I do not understand how any could result ― except in the one case which is also ruled out by the constitutional text.
The exception to Parliament’s general ability to enact electoral reform under section 44 of the Constitution Act, 1982 concerns reform plans that would sever the relationship between members of Parliament and provinces from which they are elected ― in other words, those versions of proportional representation that would distribute seats on the basis of national, rather than provincial vote totals. The trouble for such systems lies in the entrenchment, in section 41(e) of the Constitution Act, 1982 of “the right of a province to a number of members in the House of Commons not less than the number of Senators by which the province [was] entitled to be represented” in 1982, and in section 42(a), of “the principle of proportionate representation of the provinces in the House of Commons prescribed by the Constitution of Canada” (emphasis mine in both cases). It is thus the provinces ― though not any territorial subdivisions within the provinces ― that form the basis of representation in the House of Commons, and that principle is indeed part not only of the constitution’s architecture, but of its very text.
Provided that it respects this principle, however, Parliament is constitutionally free to change voting arrangements by ordinary law enacted under section 44. Such changes would, no doubt, be of great political significance. But while that may be (I think it is) an important argument in favour of giving the people a say over electoral reform, it is not, in itself, a reason to consider that constitutional amendment with provincial consent is necessary to effect such changes. The Senate Reform Reference does not hold the contrary. The question of electoral reform’s constitutionality is, I believe, a distraction from those about its desirability and the process by which its desirability ought to be determined.