The Economic Reality of Tough Immigration Laws
Gordon Hanson, an economist specializing in the impacts of immigration, studies the reality side of things at 
University of California-San Diego. He says that for decades there has been an unwritten social contract that says the U.S. isn't going to make it easy for immigrants to get in; there will be physical barriers and it will cost time, money and personal risk."
"What that did in effect was to select out people who weren't serious, to select out people for whom the opportunity of being in the United States didn't matter that much," Hanson tells weekends on All Things Considered guest host Robert Smith.