Marcy Foreman, the head of Immigration and Customs Enforcement's Office of Investigation announced that the enforcement of immigration laws against illegal aliens at their work sites has effectively ended. http://www.ilw.com/immigdaily/news/2009,1007-forman.pdf
While claiming that work site enforcement (WSE) is a priority for ICE, the memorandum acutually describes the end of WSE. Extensive new paperwork requirements are imposed with offices required to report 14 days in advance to HQ to get approval, which, of course, will not be coming. It also requires search warrants, arrest warrants and an commitment by U.S. Attorney's Offices to prosecute. As I described previously, that is unlikely. Assistant United States Attorney's are notoriously lazy and refuse to prosecute most federal crimes that law enforcement agencies bring to them. In areas like New York City, Los Angeles, and San Francisco this means a defacto amnesty for illegals and no action against employers. http://federaleagent86.blogspot.com/2009/06/its-official-back-to-future.html
Other guidelines include releasing any illegal alien who claims they are a sole custodial parent or claim they have a medical condition and now requiring notification of welfare officials of any raid involving more than 25 aliens.
All the restrictions in this memorandum are not designed to detect and deter the hiring of illegal aliens, but to discourage enforcement of immigration laws, all in support of the upcoming amnesty. Obviously the fact that U.S. Citizenship and Immigration Services was ordered to gear up for the amnesty shows that ICE Special Agents will be dragooned into USCIS to assist processing applicants for amensty, rather than arresting illegal aliens.