To be useful, it cannot be merely a government of governments - an emissary of the provinces, forbidden to do anything that does not meet with their approval. It must have a direct relationship with the citizen, unmediated by provincial interlopers. It must, as the phrase has it, appeal "over the heads of the premiers."
The Charter of Rights and Freedoms is a good example, encouraging Canadians to look to federal law and federal power to protect them from abuses of government power. Now the challenge is to extend that idea in other spheres: in the political, through such innovative means as referendums; and in the social, through reforms that put federal funds for social programs directly in the hands of individuals, rather than sending them to provincial governments.
We don't need to have Big Government in Ottawa run everything to hold together as a nation. But Big Government in the provinces will surely pull us apart.