I had a teacher once trying to tell us the founding fathers were liars, cheats, and thieves. Then went on to bash the president. I walked out and told him he's a teacher not a politician. I was going to switch teachers but went back, and he was more careful about what he said the rest of the year.
Teachers can be great if they are balanced. I had a history teacher that once pulled his Communist Party membership card out of his wallet, while the whole class sat, open-mouthed, not knowing what to say. This was in the 70s, when the USSR truly was the Evil Empire.
After he'd made his point, he showed us the card close up -- it was not a party membership card. He did it just to make a point -- that he was fully within his rights to believe in communism in the US.
He was a great teacher -- would lay out the facts, would (rarely) confess his personal belief, but would emphasize that we all had to make up our own minds.
I can see how less talented teachers view every classroom as 30 fresh, malleable minds to be won over.
Interesting, and it would solve as many problems as it would create, I think. I doubt it will happen, though, at least with Canada, because they're going to refuse to come to terms with our way of life. Free health care out the window? No way people who have had that all along are going to give it up without a huge fight. Mexico will probably jump on the bandwagon in order to strengthen their economy... but it will also strengthen ours because there will be no more of this illegal immigrants getting jobs because they'll work for $2 a hour B.S.