Here’s a simple, crazy question: is legislation limiting electoral campaign expenses unconstitutional because ultra vires the provinces? I think that the argument in support of an affirmative answer makes sense, even though I wouldn’t expect Canadian courts to buy it. Here it is.
Campaign spending restrictions restrict free speech on political matters. Nobody disputes that, and the Supreme Court recognizes this in cases such Libman v. Quebec (Attorney General),  3 S.C.R. 569. Nonetheless, such laws (if not too restrictive – as the law in Libman was found to be) can be justified under s. 1 of the Charter, and are therefore constitutional. Or are they?
In the “implied bill of rights” cases, starting with the Alberta Statutes Reference,  R.C.S. 100, the Supreme Court pushed back against attempts by the provinces (first Alberta and then Québec) to curtail political speech disagreeable to authoritarian provincial governments. As there was no Charter then, it used the federal division of powers to ground its judgments. Speech, especially political speech, was said to be within the exclusive competence of Parliament, outside the reach of provincial legislation. Whatever its subject, it was not of merely provincial importance. In the words of Chief Justice Duff and Justice Davis in the Alberta Statutes Reference, at p. 134,
[a]ny attempt to abrogate this right of public debate or to suppress the traditional forms of the exercise of the right (in public meeting and through the press) would, in our opinion, be incompetent to the legislatures of the provinces, or to the legislature of any one of the provinces, as repugnant to the provisions of The British North America Act, by which the Parliament of Canada is established as the legislative organ of the people of Canada under the Crown, and Dominion legislation enacted pursuant to the legislative authority given by those provisions. The subject matter of such legislation could not be described as a provincial matter purely; as in substance exclusively a matter of property and civil rights within the province, or a matter private or local within the province.
Saumur v. City of Québec  2 S.C.R. 299 and Switzman v. Elbing  S.C.R. 285 are to the same effect.
Overruling such hallowed precedents, showing the Supreme Court’s commitment to individual rights even in the absence of explicit constitutional authorization, seems unthinkable.
Can they be distinguished? One might argue that regulation of provincial elections, as opposed to political speech generally, is a different subject, competent to the provinces. I think the distinction fails. The passage I quote above does not really leave room for it. Provincial politics and federal politics are obviously connected, so if federal political discussion is to be free, so must provincial political discussion. But there is another possibility. It is at least a somewhat plausible reading of the “implied bill of rights” cases that what they prohibit is not any regulation of political speech by the provinces, but only, to use an American term, “viewpoint restrictions.” A province can regulate speech; it just cannot single out one opinion for unfavourable treatment. And it is perhaps arguable, though I believe (for reasons I have no room to elaborate here but touch on in my Cyberpresse op-ed) not correct, that campaign spending restrictions are viewpoint neutral. If that argument fails, as I think it should, then provincial restrictions on election spending are ultra vires and thus unconstitutional.