THE CATO INSTITUTE ON ILLEGAL IMMIGRANTS

Alan Colmes mentioned that CATO did a study of illegla immigration and concluded that the U.S. benefitted from it. I didn't find the study but I did find this article by CATO's Center for Trade Policy Studies and here's a key excerpt:

Comprehensive reform should also legalize the millions of workers currently in the United States without legal documentation. Many of these workers have lived and worked in the United States for several years. They have become valuable participants in their workplaces and their communities. They should be allowed and encouraged to come forward to be legalized and properly documented.