In Graham v. Richardson, 403 U.S. 365, 371, 29 L. Ed. 2d 534, 91 S. Ct. 1848 (1971), the Supreme Court held that "a state statute that denies welfare benefits . . . to aliens who have not resided in the United States for a specified number of years violates the Equal Protection Clause." Graham involved an Arizona statute imposing a fifteen-year residency requirement on aliens in order to qualify for county benefits. Id. at 367. In evaluating the constitutionality of the residency requirement, the Court applied a strict scrutiny analysis. Id. at 376. Under the strict scrutiny standard, the Court held that preserving limited welfare benefits for the state's own citizens did not justify a state classification based on alienage. Id. at 374-75. In addition, the Court compared the state residency requirement to federal immigration laws, which, at that time, did not impose any restrictions on aliens' eligibility for benefits. Id. at 377. Because Arizona's law conflicted with "these overriding national policies in an area constitutionally entrusted to the Federal Government" and therefore "encroached upon exclusive federal power," the state law was constitutionally impermissible. Id. at 378, 380. In a footnote, the Graham Court left open the question whether Congress, rather than the states, could impose a uniform residency requirement as a condition of federally funded welfare benefits. Id. at 382 n.14. Five years after Graham, the Court addressed this question in Mathews, 426 U.S. at 69. In Mathews, the Supreme Court upheld a restriction imposed by Congress, which denied federal health care benefits to aliens unless they had been admitted for permanent residence and also had resided in the United States for a five-year period. Id. at 70 (upholding 42 U.S.C. 1395o (1970 ed., Supp. IV)). The Supreme Court recognized that Congress has a legitimate basis for distinguishing among aliens because of its exclusive responsibility for regulating the relationship between the United States and aliens. Id. at 81. The Court noted that immigration policy "may implicate our relations with foreign powers, and . . . a wide variety of classifications must be defined in the light of changing political and economic circumstances." Id. The Court further held that "it is the business of the political branches of the Federal Government, rather than that of either the States or the Federal Judiciary, to regulate the conditions of entry and residence of aliens." Id. at 84. On the other hand, the Court concluded that states have no similarly legitimate justification for discriminating against aliens. Id. at 84-85.