Overall, I like the idea of an "NAU" (North American Union), like the EU in Europe (re: the site: http://www.unitednorthamerica.org).
However, why is Mexico excluded? Because it is a "Third World" country? Because English is not one of its major languages?
In addition, in any "NAU," measures must be taken to assure that the United States would not achieve an even greater degree of cultural hegemony over its neighbors to the south and north.