Kickbacks from big business who want a continuing supply of cheap labor.
The aspect of the big business / cheap labor angle that is being under-reported is how this will affect jobs OTHER than picking lettuce. From Business Week Online (Friday 5/18):
A ‘Troubled’ Immigration Reform Proposal
by Lorraine Woellert and Eamon Javers
The proposal would also increase the number of high-skill workers who could come to the U.S. with certain conditions. The annual cap for the temporary work visas known as H-1Bs would be increased to 115,000, from 65,000. The cap could also be increased 20% per year based on demand, not to exceed 180,000 per year. Technology companies, including Intel (INTC), Motorola (MOT), and Hewlett-Packard (HPQ), have been pushing for an increase.
“America’s need for highly skilled workers has never been greater,” said Bill Gates, chairman of Microsoft (MSFT), when he testified before the Senate in March (see BusinessWeek.com, 3/8/07, “Gates to Senate: More Visas”). “Broad-based prosperity in America depends on having enough such workers to satisfy our demand.”
Yet while tech executives were pleased with the increase in temporary work visas, they had concerns about the proposed path to permanent residency for skilled workers. Now even after talented workers have been accepted for citizenship, they can wait five or more years to get their green card.