I know there are many causes, but I'm starting to conclude that America's "immigration disaster" had its greatest surge in influence when the United Farmworkers Union, led by Cesar Chavez began to wield extraordonary legal and political power.

The UFW, sometimes lauded for adopting a closed borders policy to protect its members work, also contributed to the demise of mechanization in farming in the areas closest to the US southern border. A landmark lawsuit took place in 1979 when the UFW and the Calfornia Rural Legal Assistance filed claims against the University of California at Davis. It asserted mechanized harvesting both unfairly benefited wealthy farmers and hurt small farms, but also deprived the farmworkers group of labor. So, labor saving technology that would have helped US agriculture remain competitive in a globalized agriculture economy went into a long decline.

Over the years farmwork has been the doorway into American society and I wonder how many second and third generation descendants of 1960's farmworkers we are now seeing claim their place in the US. Agricultural interests in other states quickly found out the extreme advantages of a migrant labor population. I remember as a youth meeting Hispanic farmworkers who traveled far and wide to take part in the next harvest.

How was a group of uneducated "peasants" able to take on a major state university? I have found that farmworkers have gotten pretty good at filing other lawsuits to advance their interests. The bright spot is that American agriculture is waking up to the fact that mechanization is necessary to remain competitive in this new world economy. Here is a good article summarizing the main facets in this history that has changed the US.
http://www.mindfully.org/Farm/2004/Chea ... 2mar04.htm
It suggests that ten percent of farmworkers leave that industry every year for other vocations.