It is hard to wring money out of a rock and these places are dirt poor which is why the people are fleeing. We would be taking on a huge welfare burden and at a minimum all 100 million of those people would be collecting the Earned Income Tax Credit and food stamps just like they do in Puerto Rico.
West Germany tried this with East Germany and to-date the experment has been far from satisfactory.
Yes but Mexico has a great deal of Oil, monies from this could be used to help all of us. The would lower tha Oil imported to the US from Islamic countries and would offer greater exploration of oil in the Mexican areas.