Why do people keep falling for the NAU urban legend?
Something on that scale is a sovereignty issue in Canada.
Why? Because it’s a kingdom, not a republic like the United States.
Different country, different culture, different laws.
Sovereignty issues require amendments to the Canadian Constitution.
By law, that requires the unanimous consent of both houses of Canada’s Federal government and both houses of government of all 10 Canadian Provinces.
And that won’t ever happen because Canadians don’t want any part of the US or its national debt.
Hell, they fought (and won) wars to keep from becoming American.
(During the American Revolution and again during the War of 1812.)
Which begs the question of where all these gullible people come from that just believe nonsense like the North American Union.