A piece I read recently on the idea of CANZUK (the union of Canada, Austalia, New Zealand, and the UK) proposes Calgary as the capital. Their logic is, first, that the capital cannot be in the UK, and second, that Calgary is roughly equidistant from everyone.
I take their first point. The UK is already likely to dominate by population, and the equality of member states must be underlined. Australia and Canada are not going to sign on for a revival of the British Empire.
But as to the second—Calgary seems to qualify as equidistant from all other capitals, but only by being equally remote from everyone. Nobody chooses a capital on that basis—otherwise Australia would be administered from Alice Springs, and Canada from Churchill, Manitoba. Calgary is also profoundly landlocked, and this is unsuitable for the capital of an essentially maritime nation, connected historically and geographically by the oceans.
The capital should, of course, be Montreal. A seaport, convenient to Ottawa, and the closest large city outside the British Isles to the bulk of the union population in the British Isles. Montreal has such cultural and historical heft that it seems entitled to be the capital of somewhere, and so far it is the capital of nowhere. Moreover, its choice as capital might help convince Francophone Quebec to support the notion of joining this vast Anglophone endeavour. Once made capital, it would serve as insurance that Quebec not in future want to separate.
I even see an ideal site for the new administrative complex: the Place des Nations end of Ile Ste. Helene, built for Expo 67, now a park. It is available, it is close to downtown, it is linked by rapid transit, and, as an island shaped like a ship’s prow, it is symbolically appropriate for this maritime trading union.