There are White-racist reactionaries in the U.S. who hate Mexicans. Many of those reactionaries point to Aztlan to generate fear in the hearts of more borderline reactionaries. Aztlan is a place based upon U.S. Southwestern and Mexican Indian legend. What the reactionaries are pushing is the idea that there are Mexicans out to take back the American Southwest (part of Aztlan) from the United States.
Well, in reaction to the reactionaries, there are pro-immigrant forces that seek to dispel the tactics of the reactionaries by denying Aztlan and calling it only a white-rightwing-conspiracy theory.
According to our understanding, Aztlan is an ancient story that predates the Spanish incursion into the Southwestern U.S. by some number of centuries. Also, there is no doubt that the U.S., under what is called Polk's War, stole the Southwestern U.S. from Mexico by force of arms. It was naked aggression to expand the U.S. Empire.
As for the North American Union, it is a fact that the U.S., Mexico, and Canada are in on-going talks that have resulted in deals whereby those three nations will more and more harmonize their laws for the sake of capitalist trade. Mexican trucks are being allowed to rumble down U.S. highways to, among other things, make truck-driver wages lower in the U.S. Also, NAFTA became law and didn't do nearly any of what was promised. The executive branches of the three nations are looking at the ever-increasing economic clout of the European Union. In addition, the global plutocrats seek the continual consolidation of the governmental power of the world for their own sakes (the sakes of those plutocrats).
If the motivations were good, we'd be all for it. If the motivations were Christlike in a completely consensual and voluntary manner where everyone is convinced to come together in the spirit of the New Commandment, we'd be all for it. However, these are secretive, selfishly motivated talks and actions that are going on where the interests of the whole people are not truly being taken into account. The powers that be, who don't serve God, are coercing the peoples of the three nations into a falsely unified house that can not stand upon such coercive premises.