[Excerpt] The extent to which residents of the United States who are not U.S. citizens should be eligible for federally funded public aid has been a contentious issue since the 1990s. This issue meets at the intersection of two major policy areas: immigration policy and welfare policy. Over the past 16 years, Congress has enacted significant changes in U.S. immigration policy and welfare policy. Congress has exercised oversight of revisions made by the 1996 welfare reform law (the Personal Responsibility and Work Opportunity Reconciliation Act, P.L. 104-193)—including the rules governing noncitizen eligibility for public assistance that it established—and legislation covering programs with major restrictions on noncitizens’ eligibility (e.g., food stamps/SNAP, Medicaid). This report deals with the four major federal means-tested benefit programs: the Supplemental Nutrition Assistance Program (SNAP, formerly food stamps), the Supplemental Security Income (SSI) program, Temporary Assistance for Needy Families (TANF) block grant programs, and Medicaid. It is organized into four main parts: an overview of existing eligibility law for the four programs and the policies that preceded the 1996 act; an overview of related immigrant policies affecting eligibility (specifically, the treatment of sponsored aliens); an analysis of trends in noncitizen poverty and benefit use; and a summary of the eligibility rules for aliens residing in the United States illegally. Appendices at the conclusion elaborate on the specifics of current eligibility rules for the four major programs.