Replies

oh, well...
Option One:
militarily annex Mexico.
rebuild their industrial base.
make english the standard language.
completely erase their culture and replace it with our own.
start them on a 25-year plan towards self-determination.
after 25 years, allow them to elect to become a set of States within the USA or go their own way.

Option Two:
Seed the border with AP landmines
Make English the sole official language of the US, making public display or official use of any other language in signs or documents punishable by stiff fines and community service.
Immediately cease all government-fostered shipments of medical technology, innoculations, and foodstuffs to Mexico. Ban American charities from operating in Mexico as well.
Let the malthusian principles run their course.

Option Three:
Stop-gap efforts designed to regulate the flow of migrants.
Make America English Only. see above.
Register all immigrants. Fingerprint them. Foot-print them. Mugshot them. Make dental records of them. DNA sample them. Lojack-chip them if need be.
Sternly enforce American laws upon immigrants, and severely restrict their rights until and unless they naturalize, pass muster, and swear the Oath.
Enforce and encourage cultural assimilation to American norms.
Support economic and industrial progress in Mexico, so that that country becomes more functional and the desire to flee form it becomes less urgent and prevalent.
Do whatever is possible to get their birth-rate down to something within reason.
Cross fingers and pray.