[JumpCrisscross]

> Even serious discussion of Chinese soldiers in Canada or Mexico is clear casus belli and surefire way for those countries to be occupied

Which is why military alliance discussions aren’t conducted in public. The series of announcements would be e.g. Xi visiting Ottawa for trade talks and then announcing that Canada is under its nuclear umbrella.

> Canada is absolutely indefensible with no strategic depth or ability to get new supplies. Mexico is harder to occupy but their military is a joke and again easy to block all external supplies

Which is why they’ve sought external security guarantees. Now that America is threatening invasion, its security guarantees are diluted. So you need someone else; the only option is China (unless the EU beefs up).

[mcv]

I don't really think China is an option either. Maybe for the west coast, but I really don't think they can do much for the eastern half of Canada. Though EU+China might do it.

Problem is, China might be happy to see the US invade Canada, because then they can finally take Taiwan. And that's the real danger of Trump's foolish aggression: by weakening American's alliances, he's giving China more space to assert itself and take what they want.