I have a question for those who are worried about the reconquista phenomenon:
Self-evident as it is that the federal government (carrying out the will of most people in the USA) will slaughter any number of people who try to secede from Union, regardless of the race/creed/rationale of the secessionists, what do you think will become of this reconquista movement if it hypothetically made it to that critical point? (And no, I'm not saying that the Civil War wasn't about slavery, because each person who fights makes up their own mind as to what the war means to them.) Mexicans are smart enough to figure that out the inevitable outcome, too, as if anything close to the necessary percentage of Mexican immigrants came to America in order to reconquer it rather than to flee their dumpy homeland.
Sure, you can show me evidence that there are people who are advocating and planning a reconquista-type operation in the Southwest, but I can just as easily show you the campaigns of Ron Paul and Dennis Kucinich, or a movie like "Jesus Camp"--in all these cases, a movement is afoot that is quite sizable, and seems radical and threatening to the majority of Americans and their way of life, but that doesn't have remotely enough support to accomplish its goals. Certainly, it is difficult to mark the point where a bunch of ineffectual crackpots (the reconquistas, in this case) becomes the next National Socialist Worker's Party, but it's probably around the time when the next SA is shooting it out in the streets with their opponents or marching around major cities in uniform--you know, like actually happened in Weimar Germany.
Sure, I live in Chicago most of the time, but I do so in a dorm with people from Dallas, Houston, Sugarland, Austin, Santa Fe, Phoenix, San Diego...these are smart people who are by no means blinded by leftist ideology (okay, the one from Santa Fe is), and they have never reported any rumblings of nascent nationalist rebellion among the Mexican population; for that matter, neither has my cousin, who is a hyper-conservative former marine and Flagstaff cop. Time may vindicate you guys, but I'll be no less prepared for such an event than I would be if I thought there were a snowball's chance in Tucson of Mexicans trying to retake part of the Southwest.