Making Canada the 51st state would make it the largest continental one, usurping Texas. While I wouldn't support the idea seriously, triggering maga Texans with the idea is hilarious.

Even today amongst a certain segment of Americans they still revere the concept of “Manifest Destiny”, whereby the entirety of North America will eventually be under American (and traditionally, white Christian) rule.

This wasn’t always envisioned as being done via force; typically it was simply believed that the American system was so perfect and blessed by God that everyone in North America would eventually want to be part of it, and would simply join the US as an inevitable eventuality. To their minds, the entire concept of full American control of North America was ordained by God itself, and so couldn’t be wrong.

Of course, as with any pseudo-religious prophesies when the expectation doesn’t happen some will want to cause/force it to happen. When their Manifest Destiny doesn’t come to fruition, it’s not because of a fault in the concept (to their minds), but that the Canadians/Mexicans (and now Greenlanders?) are standing in the way of inevitability.

There are Americans who continue to believe they’ll eventually control all of North America. You can’t just ignore them and pretend they don’t exist.

This is just goading and manipulation to get better leverage on those tariffs, which is real. I don't know the scam he's aiming for here. It just feels like everyone is going to suffer an inflationary war.