What would happen if canada sent a diplomatic note stating that it intended to exercise its prerogatives under article xi of the articles of confederation and article vi of the us constitution?

Answer 1

The question is what would happen if Canada choose to join the United States and accept the supremacy of the U.S. Constitution. No one knows and the question invites everyone to add to this answer with their own ideas, so I'll start.

If such a note had not been preceded by debates and votes within Canada it would create a political crisis in Canada and might ruffle some feathers south of the border. Without the debates and votes such a note would lack legitimacy and would likely not be accepted by the U.S. and certainly not by citizens of Canada.

If such debates and votes lead to such a note it would be one formal step in a long process. A process many believe is already occurring.

Or a process that many believe will never occur. The U.S. of the 21st century has little need to invite Canada to join them. It might actually be counter-productive as the new members would gain rights they currently do not have.

There is no need to grant those rights to have military control over Canada, the U.S. already has that, Just as there is no need to grant admission to gain unfettered access to Canadian resources.

It could be argued that any such move by Canada would be blocked by an amendment to the U.S. Constitution long before Canada could send such a note. The U.S. already has what it wanted from Canada and without the costs that would come with admitting Canada into their Union.