The system seriously needs an overhaul. We need to regulate the passage of immigrants into the country, but at the same time not choke it because like it or not, our country is in part dependent on Mexican workers.
http://www.doleta.gov/agworker/report9/toc.cfm
"Foreign-born workers comprised a large share of the hired crop labor force in fiscal years 2001-2002. Among all crop workers, 78 percent were born outside the United States: seventy-five percent were born in Mexico, two percent were from Central American countries, and one percent of the workers were from elsewhere"