The characteristics of illegal immigrants emerge in studies about those who sought amnesty in 1986 under the general provisions of IRCA (as distinct from those who applied as agricultural workers). The heavy majority of the formerly illegal aliens were from Mexico (70 percent), and most were working-age men (Neuman and Tienda, 1994). Most illegal immigrants reside in only a few states, with about 40 percent living in California.
One effect of IRCA was to greatly reduce the number of illegal immigrants residing in the United States—in a sense by redefinition, because it gave amnesty to those who could prove long-time residence. Yet, even with this fiat, tougher border enforcement, and the requirement that employers check new employees for legal residence, the number of illegal immigrants is estimated to have reached about 3 to 5 million in 1996, about the same level as before IRCA (Warren, 1996).
Current estimates of net illegal immigration are in the range of 200,000 to 300,000 per year, with some consensus that the number has been closer to the high end of the range in recent years (Warren, 1996; U.S. Bureau of the Census, 1996). A lot more people go back and forth across the border illegally. Moreover, it is believed, about 40 percent of the net addition of illegal immigrants were those who entered the United States legally, as nonimmigrant students or as tourists.
Although the United States has long directed the Border Patrol to restrict the entry of illegal immigrants, public concern about large numbers of illegal immi-