Canada physically looks like the U.S. Canadians are nothing like Americans, though. Culturally. I didn't notice it until a prof spent a lecture on it... it's really true.
These are all generalizations, of course. Please don't think I speak on behalf of All Canadians, or that I think All Americans think this way. Generalizations!
*We are multicultural. Truly. I'll bet most Americans really cannot fathom this. They might think they can, but if they have not spent more than a few months outside their country in a multicultural country, then I highly doubt it. Absolutely no offense intended, it's just true.
This would be lost.
*Americans feel a need to be patriotic: the government often sets this up to get the people to follow them. If you don't agree with the government's agenda, you must not be patriotic. These are not necessarily related, but many Americans think so. Canadians don't feel patriotic--we're proud to be Canadian, but it's totally different.
*You government basically wants our water. (We own something ridiculous like 25% of the world's freshwater). We also have ridiculous amounts of energy resources that your government already manipulates out of us. We aren't politically strong enough to say no, it's bullied out of us.
*this would pretty much be an attempt to take over the world... and I highly doubt a "live and let live" mentality is going to work. People are going to get screwed, and WWIII would happen, is my guess. Which means nukes, of course.