The Immigration and Naturalization Services’ use of employer sanctions to deter illegal immigrant workers has failed in practice, prompting the INS to reevaluate its immigration strategies. The INS has quietly slashed its work site enforcement by as much as 97% over the past two years. Employer sanctions have been ineffective because of “a booming market in phony documents, the needs of employers to fill their job openings, widespread resistance to the creation of a national identification card … and politics.”
See "INS Penalty System Falls Down on Job", Jonathan Peterson, Los Angeles Times, August 5, 2001