your first instinct was a military operation?

the US has acquired territories before from a couple people in those territories realizing it was a magical way for unrelated tariffs to disappear.

history gives you the blueprint, the writing is on the wall

Honestly, Canada merging with the US would not be a bad thing. There are articles discussing Canada joining the EU. What’s the difference between being a state within the US and a country that is basically a state, within the EU? A lot of Canada - especially outside of certain cities like Vancouver - share foundational values with the US much more so than the EU.