The question presented by the Secretary's appeal is whether Congress may condition an alien's eligibility for participation in a federal medical insurance program on continuous residence in the United States for a five-year period and admission for permanent residence. The District Court held that the first condition was unconstitutional and that it could not be severed from the second. Since we conclude that both conditions are constitutional, we reverse.

Each of the appellees is a resident alien who was lawfully admitted to the United States less than five years ago. Appellees Diaz and Clara are Cuban refugees who remain in this country at the discretion of the Attorney General; appellee Espinosa has been admitted for permanent residence. All three are over 65 years old and have been denied enrollment in the Medicare Part B supplemental medical insurance program established by § 1831 et seq. of the Social Security Act of 1935, 49 Stat. 620, as added, 79 Stat. 301, and as amended, 42 U.S.C. 1395j et seq. (1970 ed. and Supp. IV).1 They brought this action to challenge the statutory basis for that denial. Specifically, they attack 42 U.S.C. § 1395o (2) (1970 ed., Supp. IV), which grants eligibility to resident citizens who are 65 or older but denies eligibility to comparable aliens unless they have been admitted for permanent residence and also have resided in the United States for at least five years.2 Appellees Diaz and Clara meet neither requirement; appellee Espinosa meets only the first.

On August 18, 1972, Diaz filed a class action complaint in the United States District Court for the Southern District of Florida alleging that his application for enrollment had been denied on the ground that he was not a citizen and had neither been admitted for permanent residence nor resided in the United States for the immediately preceding five years. He further alleged that numerous other persons had been denied enrollment in the Medicare Part B program for the same reasons. He sought relief on behalf of a class of persons who have been or will be denied enrollment in the Medicare insurance program for failure to meet the requirements of 42 U.S.C. § 1395o (2) (1970 ed., Supp. IV). Since the complaint prayed for a declaration that § 1395o (2) was unconstitutional and for an injunction requiring the Secretary to approve all applicants who had been denied eligibility solely for failure to comply with its requirements, a three-judge court was constituted.

On September 28, 1972, the District Court granted leave to add Clara and Espinosa as plaintiffs and to file an amended complaint. That pleading alleged that Clara had been denied enrollment for the same reasons as Diaz, but explained that Espinosa, although a permanent resident since 1971, had not attempted to enroll because he could not meet the durational residence requirement, and therefore any attempt would have been futile. The amended complaint sought relief on behalf of a subclass represented by Espinosa that is, aliens admitted for permanent residence who have been or will be denied enrollment for failure to meet the five-year continuous residence requirement as well as relief on behalf of the class represented by Diaz and Clara.3

On October 24, 1972, the Secretary moved to dismiss the complaint on the ground, among others, that the District Court lacked jurisdiction over the subject matter because none of the plaintiffs had exhausted his administrative remedies under the Social Security Act. Two days later, on October 26, 1972, Espinosa filed his application for enrollment with the Secretary. He promptly brought this fact to the attention of the District Court, without formally supplementing the pleadings.

None of the appellees completely exhausted available avenues for administrative review. Nevertheless, the Secretary acknowledged that the applications of Diaz and Clara raised no disputed issues of fact and therefore e interlocutory denials of their applications should be treated as final for the purpose of this litigation. This satisfied the jurisdictional requirements of 42 U.S.C. § 405(g). Weinberger v. Salfi, 422 U.S. 749, 763-767, 95 S.Ct. 2457, 2465-2467, 45 L.Ed.2d 522, 537-539; Weinberger v. Wiesenfeld, 420 U.S. 636, 641 n. 8, 95 S.Ct. 1225, 1230, 43 L.Ed.2d 514, 520-521. The Secretary did not make an equally unambiguous concession with respect to Espinosa, but in colloquy with the court he acknowledged that Espinosa had filed an application which could not be allowed under the statute.4 The District Court overruled the Secretary's motion to dismiss and decided the merits on cross-motions for summary judgment.

The District Court held that the five-year residence requirement violated the Due Process Clause of the Fifth Amendment5 and that since it could not be severed from the requirement of admission for permanent residence, the alien-eligibility provisions of § 1395O (2)(B) were entirely unenforceable. Diaz v. Weinberger, 361 F.Supp. 1 (1973). The District Court reasoned that "even though fourteenth amendment notions of equal protection are not entirely congruent with fifth amendment concepts of due process," Id., at 9, the danger of unjustifiable discrimination against aliens in the enactment of welfare programs is so great, in view of their complete lack of representation in the political process, that this federal statute should be tested under the same pledge of equal protection as a state statute. So tested, the court concluded that the statute was invalid because it was not both rationally based and free from invidious discrimination. It rejected the desire to preserve the fiscal integrity of the program, or to treat some aliens as less deserving than others, as adequate justification for the statute. Accordingly, the court enjoined the Secretary from refusing to enroll members of the class and subclass represented by appellees.

The Secretary appealed directly to this Court.6 We noted probable jurisdiction. Weinberger v. Diaz, 416 U.S. 980, 94 S.Ct. 2381, 40 L.Ed.2d 757. After hearing argument last Term, we set the case for reargument. 420 U.S. 959, 95 S.Ct. 1346, 43 L.Ed.2d 436. We now consider (1) whether the District Court had jurisdiction over Espinosa's claim; (2) whether Congress may discriminate in favor of citizens and against aliens in providing welfare benefits; and (3) if so, whether the specific discriminatory provisions in § 1395o (2)(B) are constitutional.

* Espinosa's claim squarely raises the question whether the requirement of five years' continuous residence is constitutional, a question that is not necessarily presented by the claims of Diaz and Clara. For if the requirement of admission for permanent residence is valid, their applications were properly denied even if the durational residence requirement is ineffective.7 We must therefore decide whether the District Court had jurisdiction over Espinosa's claim.

We have little difficulty with Espinosa's failure to file an application with the Secretary until after he was joined in the action. Although 42 U.S.C. § 405(g) establishes filing of an application as a nonwaivable condition of jurisdiction, Mathews v. Eldridge, 424 U.S. 319, 328, 96 S.Ct. 893, 899, 47 L.Ed.2d 1829 (1976); Weinberger v. Salfi, 422 U.S., at 764, 95 S.Ct., at 2466, 45 L.Ed.2d, at 538, Espinosa satisfied this condition while the case was pending in the District Court. A supplemental complaint in the District Court would have eliminated this jurisdictional issue;8 since the record discloses, both by affidavit and stipulation, that the jurisdictional condition was satisfied, it is not too late, even now, to supplement the complaint to allege this fact.9 Under these circumstances, we treat the pleadings as properly supplemented by the Secretary's stipulation that Espinosa had filed an application.

A further problem is presented by the absence of any formal administrative action by the Secretary denying Espinosa's application. Section 405(g) requires a final decision by the Secretary after a hearing as a prerequisite of jurisdiction. Mathews v. Eldridge, supra, 424 U.S. 319, 328-330, 96 S.Ct. 893, 899-900, 47 L.Ed.2d 18, 29-30; Weinberger v. Salfi, supra, 422 U.S. at 763-765, 95 S.Ct. at 2465, 2467, 45 L.Ed.2d at 537-539. However, we held in Salfi that the Secretary could waive the exhaustion requirement which this provision contemplates and that he had done so in that case. Id., at 765-767, 95 S.Ct. at 2467-2468, 45 L.Ed.2d at 538-540; accord, Mathews v. Eldridge, supra, 424 U.S. 319, 328-330, 96 S.Ct. 893, 899-900, 47 L.Ed.2d 18, 29-30 (dictum); Weinberger v. Wiesenfeld, 420 U.S., at 641 n. 8, 95 S.Ct. 1225, 1230, 43 L.Ed.2d 514, 520-521. We reach a similar conclusion here.

The plaintiffs in Salfi alleged that their claims had been denied by the local and regional Social Security offices and that the only question was one of constitutional law, beyond the competence of the Secretary to decide. These allegations did not satisfy the exhaustion requirements of § 405(g) or the Secretary's regulations, but the Secretary failed to challenge the sufficiency of the allegations on this ground. We interpreted this failure as a determination by the Secretary that exhaustion would have been futile and deferred to his judgment that the only issue presented was the constitutionality of a provision of the Social Security Act.

The same reasoning applies to the present case. Although the Secretary moved to dismiss for failure to exhaust administrative remedies, at the hearing on the motion he stipulated that no facts were in dispute, that the case was ripe for disposition by summary judgment, and that the only issue before the District Court was the constitutionality of the statute.10 As in Salfi, this constitutional question is beyond the Secretary's competence. Indeed, the Secretary has twice stated in this Court that he stipulated in the District Court that Espinosa's application would be denied for failure to meet the durational residence requirement.11 For jurisdictional purposes, we treat the stipulation in the Distct Court as tantamount to a decision denying the application and as a waiver of the exhaustion requirements. Cf. Weinberger v. Wiesenfeld, supra, at 640 n. 6, 641 n. 8, 95 S.Ct. at 1230, 43 L.Ed.2d at 520-521.

We conclude, as we did in Salfi, that the Secretary's submission of the question for decision on the merits by the District Court satisfied the statutory requirement of a hearing and final decision. We hold that Espinosa's claim, as well as the claims of Diaz and Clara, must be decided.

There are literally millions of aliens within the jurisdiction of the United States. The Fifth Amendment, as well as the Fourteenth Amendment, protects every one of these persons from deprivation of life, liberty, or property without due process of law. Wong Yang Sung v. McGrath, 339 U.S. 33, 48-51, 70 S.Ct. 445, 453-455, 94 L.Ed. 616, 627-629; Wong Wing v. United States, 163 U.S. 228, 238, 16 S.Ct. 977, 981, 41 L.Ed. 140, 143; see Russian Fleet v. United States, 282 U.S. 481, 489, 51 S.Ct. 229, 231, 75 L.Ed. 473, 476. Even one whose presence in this country is unlawful, involuntary, or transitory is entitled to that constitutional protection. Wong Yang Sung, supra ; Wong Wing, supra.

The fact that all persons, aliens and citizens alike, are protected by the Due Process Clause does not lead to the further conclusion that all aliens are entitled to enjoy all the advantages of citizenship or, indeed, to the conclusion that all aliens must be placed in a single homogeneous legal classification. For a host of constitutional and statutory provisions rest on the premise that a legitimate distinction between citizens and aliens may justify attributes and benefits for one class not accorded to the other;12 and the class of aliens is itself a heterogeneous multitude of persons with a wide-ranging variety of ties to this country.13

In the exercise of its broad power over naturalization and immigration, Congress regularly makes rules that would be unacceptable if applied to citizens. The exclusion of aliens14 and the reservation of the power to deport15 have no permissible counterpart in the Federal Government's power to regulate the conduct of its own citizenry.16 The fact that an Act of Congress treats aliens differently from citizens does not in itself imply that such disparate treatment is "invidious."

In particular, the fact that Congress has provided some welfare benefits for citizens does not require it to provide like benefits for All aliens. Neither the overnight visitor, the unfriendly agent of a hostile foreign power, the resident diplomat, nor the illegal entrant, can advance even a colorable constitutional claim to a share in the bounty that a conscientious sovereign makes available to its own citizens and Some of its guests. The decision to share that bounty with our guests may take into account the character of the relationship between the alien and this country: Congress may decide that as the alien's tie grows stronger, so does the strength of his claim to an equal share of that munificence.

The real question presented by this case is not whether discrimination between citizens and aliens is permissible; rather, it is whether the statutory discrimination Within the class of aliens allowing benefits to some aliens but not to others is permissible. We turn to that question.

For reasons long recognized as valid, the responsibility for regulating the relationship between the United States and our alien visitors has been committed to the political branches of the Federal Government.17 Since decisions in these matters may implicate our relations with foreign powers, and since a wide variety of classifications must be defined in the light of changing political and economic circumstances, such decisions are frequently of a character more appropriate to either the Legislature or the Executive than to the Judiciary. This very case illustrates the need for flexibility in policy choices rather than the rigidity often characteristic of constitutional adjudication. Appellees Diaz and Clara are but two of over 440,000 Cuban refugees who arrived in the United States between 1961 and 1972.18 And the Cuban parolees are but one of several categories of aliens who have been admitted in order to make a humane response to a natural catastrophe or an international political situation.19 Any rule of constitutional law that would inhibit the flexibility of the political branches of government to respond to changing world conditions should be adopted only with the greatest caution.20 The reasons that preclude judicial review of political questions21 also dictate a narrow standard of review of decisions made by the Congress or the President in the area of immigration and naturalization.

Since it is obvious that Congress has no constitutional duty to provide All aliens with the welfare benefits provided to citizens, the party challenging the constitutionality of the particular line Congress has drawn has the burden of advancing principled reasoning that will at once invalidate that line and yet tolerate a different line separating some aliens from others. In this case the appellees have challenged two requirements first, that the alien be admitted as a permanent resident, and, second, that his residence be of a duration of at least five years. But if these requirements were eliminated, surely Congress would at least require that the alien's entry be lawful; even then, unless mere transients are to be held constitutionally entitled to benefits, Some durational requirement would certainly be appropriate. In short, it is unquestionably reasonable for Congress to make an alien's eligibility depend on both the character and the duration of his residence. Since neither requirement is wholly irrational, this case essentially involves nothing more than a claim that it would have been more reasonable for Congress to select somewhat different requirements of the same kind.

We may assume that the five-year line drawn by Congress is longer than necessary to protect the fiscal integrity of the program.22 We may also assume that unnecessary hardship is incurred by persons just short of qualifying. But it remains true that some line is essential, that any line must produce some harsh and apparently arbitrary consequences, and, of greatest importance, that those who qualify under the test Congress has chosen may reasonably be presumed to have a greater affinity with the United States than those who do not. In short, citizens and those who are most like citizens qualify. Those who are less like citizens do not.

The task of classifying persons for medical benefits, like the task of drawing lines for federal tax purposes, inevitably requires that some persons who have an almost equally strong claim to favored treatment be placed on different sides of the line; the differences between the eligible and the ineligible are differences in degree rather than differences in the character of their respective claims. When this kind of policy choice must be made, we are especially reluctant to question the exercise of congressional judgment.23 In this case, since appellees have not identified a principled basis for prescribing a different standard than the one selected by Congress, they have, in effect, merely invited us to substitute our judgment for that of Congress in deciding which aliens shall be eligible to participate in the supplementary insurance program on the same conditions as citizens. We decline the invitation.

The cases on which appellees rely are consistent with our conclusion that this statutory classification does not deprive them of liberty or property without due process of law.

Graham v. Richardson, 403 U.S. 365, 91 S.Ct. 1848, 29 L.Ed.2d 534, provides the strongest support for appellees' position. That case holds that state statutes that deny welfare benefits to resident aliens, or to aliens not meeting a requirement of durational residence within the United States, violate the Equal Protection Clause of the Fourteenth Amendment and encroach upon the exclusive federal power over the entrance and residence of aliens. Of course, the latter ground of decision actually supports our holding today 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. The equal protection analysis also involves significantly different considerations because it concerns the relationship between aliens and the States rather than between aliens and the Federal Government.

Insofar as state welfare policy is concerned,24 there is little, if any, basis for treating persons who are citizens of another State differently from persons who are citizens of another country. Both groups are noncitizens as far as the State's interests in administering its welfare programs are concerned. Thus, a division by a State of the category of persons who are not citizens of that State into subcategories of United States citizens and aliens has no apparent justification, whereas, a comparable classification by the Federal Government is a routine and normally legitimate part of its business. Furthermore, whereas the Constitution inhibits every State's power to restrict travel across its own borders, Congress is explicitly empowered to exercise that type of control over travel across the borders of the United States.25

The distinction between the constitutional limits on state power and the constitutional grant of power to the Federal Government also explains why appellees' reliance on Memorial Hospital v. Maricopa County, 415 U.S. 250, 94 S.Ct. 1076, 39 L.Ed.2d 306, is misplaced. That case involved Arizona's requirement of durational residence within a county in order to receive nonemergency medical care at the county's expense. No question of alienage was involved. Since the sole basis for the classification between residents impinged on the constitutionally guaranteed right to travel within the United States, the holding in Shapiro v. Thompson, 394 U.S. 618, 89 S.Ct. 1322, 22 L.Ed.2d 600, required that it be justified by a compelling state interest.26 Finding no such justification, we held that the requirement violated the Equal Protection Clause. This case, however, involves no state impairment of the right to travel nor indeed any impairment whatever of the right to travel within the United States; the predicate for the equal protection analysis in those cases is simply not present. Contrary to appellees' characterization, it is not "political hypocrisy" to recognize that the Fourteenth Amendment's limits on state powers are substantially different from the constitutional provisions applicable to the federal power over immigration and naturalization.

Finally, we reject the suggestion that U. S. Dept. of Agriculture v. Moreno, 413 U.S. 528, 93 S.Ct. 2821, 37 L.Ed.2d 782, lends relevant support to appellees' claim. No question involving alienage was presented in that case. Rather, we found that the denial of food stamps to households containing unrelated members was not only unsupported by any rational basis but actually was intended to discriminate against certain politically unpopular groups. This case involves no impairment of the freedom of association of either citizens or aliens.

We hold that § 1395o (2)(B) has not deprived appellees of liberty or property without due process of law.

Reversed.