Guest worker program in Mexico

There’s an AP story about President Calderón’s call for immigration reform in Mexico, which includes making illegal immigration a civil rather than criminal offense, improving conditions at detention center, and expanding a guest worker program.

That’s right, a guest worker program, aimed at Central Americans:

Details have not been released, but experts expect an expansion of Mexico's seasonal farm worker program, which issues at least 40,000 temporary visas a year, mostly to Guatemalans. Most work in coffee plantations in southern Chiapas state, and many often face problems over pay, medical care and housing.

Migration experts say Calderon wants to stop those abuses while also allowing Central Americans to work in the construction and service industries in the south.

I have to admit that I did not know Mexico had one, and it raises some questions.

• can we determine empirically what jobs will not be filled by native workers, even in a situation of high unemployment/underemployment? We’d have to address location, pay, conditions, duration, etc.

• how many Central Americans come to Mexico to work rather than continue through to the United States?

• since Mexico’s immigration laws are very harsh (far more so than in the U.S.), yet ineffective, what can that tell us about the efficacy of certain types of laws?