The following may be a bit extreme, but reality says we have a situation that calls for extreme action. I don't know the feasability of any of these since many U.S. companies sent their factories out of the country to take advantage of cheap labor.
1. Freeze all immigration from countries than encourage illegal invasion.
2. End foreign aid to Mexico and send them the bill for the costs of education, housing, healthcare of their citizens. If they refuse to pay, freeze any assests their government has in this country, or push the border further south.
3. End all student/tourist visas from said countries.
4. Close all trade with said countries. Allow none of their trucks across the border, none of their ships into American ports. Close the border to tourists going south (without US dollars, their economy collapses).
5. Expell all diplomats from said country and have them removed from U.N. representation. (I know, who cares about the U.N.)
If the above fails, then there's the military option. ANNEX MEXICO (since most of their population is here already) or topple their government and install a representative democracy not run by the Drug cartel.
Ya' hear that, VINCENTE FOX?
Annex Mexico? LOL! Not a bad suggestion, Raster.