Canada as a constituent of an imperial federation

What if Canada did not want to become independent, and how would that affect UK-US relations?

Canada might join an imperial federation as a self-governing constituent, creating a new federal state rather than remaining subordinate to Britain.

The answer first asks when Canada's constitutional path changes. It recalls discussions in the late 1890s and early 1900s about a codified federation involving Britain, Canada, Australia, and New Zealand. Malta and Gibraltar are also mentioned, with Singapore included more tentatively. The recollection carries an explicit limit: the proposals are not thought to have reached prime-ministerial level. Under this hypothetical arrangement, Canada would become a constituent of a new state with a new government. The answer does not work out a specific resulting change in UK-US relations.