I'm willing to bet there are plans on "what if" scenarios for the US military if it ever has to invade Canada or Mehico. If not to conquer them at least to defend them. It is not too far fetched for Chavez to think of himself just as Hitler did, so South America could easily see itself spiral downward. Columbia and Panama would square off vs Chanez and his goose-steppers, then who knows where the rest of the countries would fall into place. If Mexico gets hammered and eventually gets its arse handed to it in some manner, that is when the US steps in full scale.
I doubt it would ever happen, but then again this is a "what if" scenario.
Canada??? Not sure who they would scuffle with, they'd be on the defensive vs China or Russia probably then the US would step in and help its little brother out.
