It would be amusing if the surviving family did not support this underhanded move, and spoke out about it.

It would be the point of no return for the USA, and the conclusive end to the “Pax Americana” . Invading a peaceful neighbor? Unthinkable for a “so-called” stable country. The rest of the world rally to Canada’s side, there would be an effort to ‘contain’ the further damage we could do. (Mexico would finally pay for that wall :-/ ) We would no longer be trusted, and in that vacuum of power the rest of the countries of the world would be thrown into such a frenzy to fill that power, or to align with who they think could.