Congress's interest in the receipt of government assistance by noncitizens dates back to at least 1882, when the country's first general immigration law excluded aliens who were deemed "likely to become a public charge" after they came to the United States. The term public charge has historically meant persons who are "primarily dependent upon the government for subsistence," and the 1882 measure effectively limited aliens' receipt of government assistance by barring aliens who were likely to substantially rely upon such assistance from entering the United States. Since that time, Congress has returned periodically to the topic of noncitizens' eligibility for public benefits, sometimes restricting noncitizens' eligibility for public benefits and sometimes expanding it. Congressional interest has been particularly high in recent years due to the sizable number of aliens who are unlawfully present in the United States (i.e., entered without inspection, or overstayed or otherwise violated the terms of their visas). Some have suggested that noncitizens' eligibility for public benefits is a "magnet" for unauthorized immigration and ought to be further restricted. Others have sought to expand at least certain aliens' eligibility for public benefits on humanitarian or public interest grounds. Whether and when persons who are present in the United States, but not U.S. citizens or nationals, may receive particular types of government assistance can be difficult to ascertain because of the various federal, state, and local laws governing their eligibility for such assistance. The Personal Responsibility and Work Opportunity Reconciliation Act of 1996 (PRWORA) was enacted to establish "national policy with respect to welfare and immigration." With certain exceptions, PRWORA bars aliens who are not "qualified aliens" from receiving federal, state, or local "public benefits," and precludes qualified aliens from receiving federal "means-tested public benefits" for 5 or more years after they enter the United States in a qualified status. However, there are also a number of other federal, state, and local measures adopted prior to, or after, the enactment of PRWORA, some of which make different provisions for noncitizens' eligibility for particular benefits. The applications of these measures can raise complicated issues of constitutional law, statutory interpretation, and administrative law. This report provides an overview of PRWORA and illustrative pre- and post-PRWORA enactments regarding noncitizen eligibility for public benefits as background, before turning to a discussion of the major legal issues raised by such measures. The discussion of enactments other than PRWORA and the legal issues they raise is selective. The report does not attempt to identify all legal measures that might affect noncitizens' eligibility for particular benefits, or all legal issues that could potentially be raised. Rather, its focus is upon illustrative measures, and major legal issues that have recurred. The report also does not address legal issues that could potentially be raised by noncitizens' receipt of public benefits, particularly whether the receipt of such benefits may result in aliens being found to be inadmissible or deportable on public charge grounds. A separate report, CRS Report R43220, Public Charge Grounds of Inadmissibility and Deportability: Legal Overview , by [author name scrubbed], discusses these issues. There are also several CRS reports addressing policy issues related to noncitizens' eligibility for public benefits. PRWORA, as amended, establishes certain default rules regarding noncitizens' eligibility for federal, state, and local public benefits by creating various categories of aliens and benefits, and prescribing when particular aliens may receive certain benefits. However, numerous measures had been enacted prior to PRWORA, which PRWORA effectively nullified or modified. In addition, Congress, states and, in some cases, localities have enacted additional measures post-PRWORA that either expand, or restrict, noncitizens' eligibility for particular benefits. Prior to the enactment of PRWORA, there generally were no overarching rules regarding noncitizens' eligibility for public benefits. Rather, individual statutes generally governed noncitizens' eligibility for benefits provided pursuant to the statute, and often classified aliens in terms of categories specific to the statute. For example, the Unemployment Compensation Amendments of 1976 expressly prohibited the payment of unemployment insurance on the basis of services performed by an alien unless the alien was (1) a lawful permanent resident (LPR) when the services were performed; (2) "lawfully present" for purposes of performing the services; or (3) residing in the United States "under color of law" when the services were performed. Noncitizens not belonging to one of these three classes—most notably, aliens who were unlawfully present or working in the United States when they provided the services upon which compensation would be based—were barred from receiving unemployment insurance. The Social Security Amendments of 1965 similarly provided that Every individual who (1) has attained the age of 65, and (2) (A) is a resident of the United States, and is either (i) a citizen or an alien lawfully admitted for permanent residence who has resided in the United States continuously during the 5 years immediately preceding the month in which he applies for enrollment under this part ... is eligible to enroll in the [Medicare Part B] insurance program. Here, the only noncitizens eligible for Medicare Part B were LPRs who had resided in the United States "continuously" for the five years prior to applying for enrollment. All others were excluded, including LPRs who had not yet resided in the United States for five years, or whose total period of residence, while longer than five years, had not been "continuous." In yet other cases, the statute was silent as to noncitizens' eligibility for benefits provided pursuant to the statute (e.g., school lunch and nutrition, supplemental food program for women, infants, and children (WIC), earned income credit), which was often taken to mean that noncitizens were not barred from receiving such benefits. In a few cases, however, states, in particular, enacted measures that addressed noncitizens' eligibility for public benefits more broadly. Perhaps the best known of these was California's Proposition 187, adopted by voters in 1994, and described by some commentators as the "impetus" for PRWORA. Proposition 187 was intended to "prevent illegal aliens in the United States from receiving benefits or public services in the State of California." Among other things, Proposition 187 barred the provision of "public social services" and "publicly-funded health care services" to persons who were not U.S. citizens, LPRs, or "admitted lawfully for a temporary period of time." It also barred persons who were not citizens, LPRs, or "otherwise authorized under federal law to be present in the United States" from admission to public elementary, secondary, and postsecondary schools. However, these and other provisions of Proposition 187 were found to be preempted by federal law, or otherwise impermissible, and not enforced. Some of these pre-PWRORA laws remain on the books, but their implementation has generally been shaped by the subsequent enactment of PRWORA. As discussed below, PRWORA "effectively invalidated all existing" federal, state, or local measures governing noncitizens' eligibility for public benefits, replacing them with default rules that states, in particular, may opt out of only in specified circumstances (e.g., by enacting a measure subsequent to PRWORA that "affirmatively provides" for unauthorized aliens' eligibility). PRWORA has, thus, resulted in unauthorized aliens being ineligible for various state services. The U.S. Department of Education similarly modified its guidance regarding which noncitizens are eligible for federal financial aid under the Higher Education Act after PRWORA's enactment. Congress enacted PRWORA in 1996, in part, to bring a degree of uniformity to noncitizens' eligibility for federal, state, and local public benefits. When enacting PRWORA, Congress provided that the restrictions and conditions it imposed apply "[n]otwithstanding any other provision of law," except as otherwise provided in PRWORA. This language has been construed to mean that PRWORA generally "invalidated" or rendered unenforceable preexisting federal, state, and local measures, at least to the degree that these measures were inconsistent with PRWORA. Then, in place of these varied measures—which often had their own ways of describing both categories of noncitizens and particular types of benefits—PRWORA established standardized taxonomies of aliens and benefits. It also prescribed general rules regarding when particular aliens are eligible for specific benefits. Under PRWORA, aliens are divided into two basic categories: qualified and not qualified. PRWORA defines qualified alien to encompass: LPRs; aliens granted asylum; refugees; aliens paroled into the United States for a period of at least one year; aliens whose deportation is being withheld; aliens granted conditional entry; and Cuban and Haitian entrants. However, certain aliens who have been subject to domestic violence are also treated as qualified aliens for purposes of PRWORA. All other aliens are not qualified. This includes those who are unlawfully present; have been granted temporary protected status, deferred enforced departure, or deferred action; or are lawfully present in the United States on nonimmigrant visas. PRWORA similarly categorizes benefits as: federal public benefits, federal means-tested public benefits, and state and local public benefits. With certain exceptions, it defines federal and state and local public benefit s to mean the following: any grant, contract, loan, professional license, or commercial license provided by [a government] agency ... or by appropriated funds ...; and any retirement, welfare, health, disability, public or assisted housing, postsecondary education, food assistance, unemployment benefit, or any other similar benefit for which payments or assistance are provided to an individual, household, or family eligibility unit by [a government] agency ... or by appropriated funds.