According to an AP article by Mark Stevenson(4/23/06) "Mexico's economy, society and political system are built around the assumption that migration and amnesties for undocumented migrants will continue -- and that the $20 billion they send home every year will keep coming, and almost certainly grow."
Stevenson also reports that Mexicans -- the ones actually living in Mexico -- are giving their babies American names like Johnny and Leslie so that they will fit in better once they've moved to the United States.
Vicente Fox, Mexico's president, considers the illegal aliens to be "heroes." Why? Because they send those tens of millions of dollars back to their families, thus, at least to some extent, relieving Fox of the necessity of tackling corruption in the Mexican government and reforming the Mexican economy so that these people can earn that money there instead of invading the United States to get work.
There is a big difference this time. Right now, we have a President and Congress that is enabling them. And with the illegal presence in the rest of the country, there will be a lot of resistance to stopping separation.