From the 2009 Human Development Report. Steven Taylor opines:

What is interesting is that the lowest [Human Development Index (HDI)] county on the US side (Starr County Texas) is higher than the highest HDI municipality in Mexico (i.e., Mexicali).

This is, of course, likely not a shock to anyone paying even a modicum of attention to the situation.  Still, it continues to underscore that fundamental aspect of this situation:  it is the disparity of wealth between the two countries that continues to create the synergy of migration over the border.  As I keep saying:  any policy that ignores this fact will fail.  As such, calls for massive deportations or that assumes it is possible to stop migration over the border is naught more than fantasy.  “Seal the border!” is a slogan, not a viable policy.