They already have their sympathizers in place. They are already taking over parts of the U.S. Not to get all "moonbatty" and sound like a conspiracy theorist, but take a drive through parts of the U.S. and you'll see it. I'm sure you already do since it's not limited to border towns now.
Our city has been held hostage by the illegal immigration issue for years now. In fact, a dispute over a day laborer site brought the city council to it's knees. The mayor was ousted along with several other folks. Our P.D. finally got I.C.E. training and funding so they can enforce the laws and round up the illegals. But in the years since, parts of our community have been devastated. Businesses have folded, crime has gone up, property values went down, schools are overburdened with kids who can't speak a word of English, etc...and many organizations in this region are willing accomplices. One local organization passes out flyers with instructions on how to "avoid being deported" and how to "get social services".