The following explanation of Deferred Action, the tool that will be used by President Obama for the DREAMer amnesty, is from testimony I provided last summer to the U.S. House Judiciary Subcommittee on Immigration Policy and Enforcement:
Deferred action is a more formal way of exercising prosecutorial discretion that is available to USCIS, ICE and CBP. There is no statutory basis for this form of relief, but it is well established as a matter of policy. However, the lack of statutory guidelines makes it especially susceptible to abuse. Deferred action enables the government to make a formal determination not to pursue removal of an unqualified or unlawfully present individual for a specific period of time, usually for extraordinary humanitarian or law enforcement purposes. For example, some foreign students affected by Hurricane Katrina were granted deferred action, as were Haitians who fled to the United States on non-immigrant visas following the earthquake in 2010. As with other forms of relief, beneficiaries can receive a work permit.
The immigration agency has traditionally held that deferred action is a tool that exists for the convenience of the government, and is not an immigration benefit per se, and it has resisted organized pressure to formalize the application process, publicize its availability, and thereby encourage more people to apply. Because there are no statutory definitions or rules regarding grants of deferred action, many advocates for amnesty and expanded immigration have periodically tried to make the case for large-scale grants of deferred action for groups of people who have no other legal immigration options, such as the so-called DREAM Act illegal aliens. The USCIS Administrative Amnesty Memo recommended that USCIS increase use of this tool as a way of legalizing these and other large groups of illegal aliens. It also noted one problem with such a step; because there is no fee currently charged to process deferred action requests, the agency (really applicants in other legal categories) would have to cover the cost of processing all the applications, making it very hard accomplish a large-scale deferred action program.
There are no statistics available on the number of grants of Deferred Action. The USCIS Ombudsman issued a formal recommendation in 2007 that the agency provide these statistics on a quarterly basis, and repeated the recommendation in its 2011 set of requests. Congress should press USCIS and the other immigration agencies to fulfill this recommendation in order to monitor use of this extraordinary tool.