
Well, if there was one controlling force, we would know it.
I suspect there are many forces at play. Devaluation of the peso is certainly motivation for the illegals. Yes, and it makes it easier for Walmart and Home Depot to buy up Mexican stores and for IBM to get their PCs assembled. It should also make Mexican tomatoes more attractively priced in the US.
Alex
"I have a truly marvelous demonstration of this proposition which this margin is too narrow to contain. -- Pierre de Fermat (1601-1665)