delivered the opinion of the Court.

This case presents the issue whether the United States District Court for the District of Puerto Rico possesses *575jurisdiction, under 28 U. S. C. § 1343 (3),1 to entertain a suit based upon 42 U. S. C. § 1983,2 and, if the answer is in the affirmative, the further issue whether Puerto Rico’s restriction, by statute, of licenses for civil engineers to United States citizens is constitutional. The first issue, phrased another way, is whether Puerto Rico is a “State,” for purposes of § 1343 (3), insofar as that statute speaks of deprivation “under color of any State law”; the resolution of that question was reserved in Calero-Toledo v. Pearson Yacht Leasing Co., 416 U. S. 663, 677 n. 11 (1974).

I

A. Puerto Rico’s Act of May 10, 1951, No. 399, as amended, now codified as P. R. Laws Ann., Tit. 20, §§ 681-710 (Supp. 1973), relates to the practice of engineering, architecture, and surveying. The administration and enforcement of the statute, by § 683, are committed to the Commonwealth’s Board of Examiners of Engineers, Architects, and Surveyors, an appellant here. *576Section 689 3 sets forth the qualifications “for registration as licensed engineer^ architect or surveyor.” For a “licensed engineer or architect,” these qualifications in-*577elude a specified education, the passing of a written examination, and a stated minimum practical experience. The statute also requires that an applicant for registration be a citizen of the United States. It, however, exempts an otherwise qualified alien from the citizenship requirement if he has “studied the total courses” in the Commonwealth, or if he is employed by an agency or instrumentality of the government of the Commonwealth or by a municipal government or public corporation there; in the case of such employment, the alien receives a conditional license valid only during the time he is employed by the public entity.

B. Maria C. Flores de Otero is a native of Mexico and a legal resident of Puerto Rico. She is, by profession, a civil engineer. She is not a United States citizen. In June 1972 she applied to the Board for registration as a licensed engineer. It is undisputed that the applicant met all the specifications of formal education, examina*578tion, and practice required for licensure,- except that of United States citizenship. The Board denied her application until she furnished proof of that citizenship.

In October 1973 Flores instituted an action in the United States District Court for the District of Puerto Rico against the Board and its individual members. She asserted jurisdiction under 28 U. S. C. § 1343 (3),4 and alleged that the citizenship requirement was violative of her rights under 42 U. S. C. §§ 1981 and 1983. A declaratory judgment and injunctive relief were requested.

In their answer to Flores’ complaint, the defendants alleged that the United States District Court lacked jurisdiction to entertain the complaint, and that the provisions of § 689 did not contravene rights secured under the Fifth and Fourteenth Amendments or any rights guaranteed to Flores under the Constitution. They also alleged that Flores had adequate remedies available to her in the courts of Puerto Rico and that she had not exhausted those remedies. They requested that the court “abstain from assuming jurisdiction in this case and allow the Courts of the Commonwealth of Puerto Rico the opportunity to pass upon the issues raised by plaintiff.” App. 5.

C. Sergio Perez Nogueiro is a native of Spain and a legal resident of Puerto Rico. He is, by profession, a civil engineer. He possesses degrees from universities in Spain and Colombia and from the University of Puerto Rico. He is not a United States citizen. He, like Flores, met all the specifications of formal education, examination, and practice required for licensure, except *579that of United States citizenship. He is presently employed as an engineer by the Public Works Department of the municipality of Carolina, Puerto Rico, and holds a conditional license granted by the Board, as authorized by § 689, after he passed the required examination.5

In May 1974 Perez instituted an action against the Board6 in the United States District Court for the District of Puerto Rico. He asserted that the citizenship requirement “is repugnant to the Due Process Clause of the Fifth or Fourteenth Amendments.” App. 10. The complaint in all relevant respects was like that filed by Flores, and Perez, too, requested declaratory and in-junctive relief, including a full and unconditional license to practice as an engineer in the Commonwealth.

D. A three-judge court was convened to hear Flores’ case. It determined that it had jurisdiction under §§ 1983 and 1343. It concluded that abstention was unnecessary because § 689 was unambiguous and not susceptible of an interpretation that would obviate the need for reaching the constitutional question. On the merits, with one judge dissenting, it rejected the justifications proffered by the defendants for the citizenship requirement. It found that requirement unconsti*580tutional and directed the defendants to license Flores as an engineer.

In a separate and subsequent judgment the same three-judge court, by the same vote, granted like relief to Perez. It decreed that he, too, be licensed as an engineer. Jurisdictional Statement 7a.

Appeals were taken by the defendants from both judgments, with a single jurisdictional statement pursuant to our Rule 15 (3). We noted probable jurisdiction and granted a stay of the execution and enforcement of the judgments. 421 U. S. 986 (1975).

II

On the jurisdictional issue, the appellants do not contend that the United States Constitution has no application in Puerto Rico7 or that claims' cognizable under § 1983 may not be enforced there. Instead, they argue that unless a complainant establishes the $10,000 juris•dictional amount prescribed by 28 U. S. C. § 1331 (a),8 a claim otherwise cognizable under § 1983 must be adjudicated in the courts of Puerto Rico.9

In approaching this question we are to examine the language of § 1343, the purposes of Congress in enacting it, “and the circumstances under which the words were employed.”10 Puerto Rico v. Shell Co. (P. R.), *581Ltd., 302 U. S. 253, 258 (1937); District of Columbia v. Carter, 409 U. S. 418, 420 (1973). As is so frequently the case, however, the language is not free of ambiguity, the purposes appear to be diverse and sometimes contradictory, and the circumstances are not fully spread upon the record for our instruction.

A. The federal civil rights legislation, with which we are here concerned, was enacted nearly 30 years before the conflict with Spain and the resulting establishment of the ties between Puerto Rico and the United States. Both § 1343 (3) and § 1983 have their origin in the Ku Klux Klan Act of April 20, 1871, § 1, 17 Stat. 13. That statute contained not only the substantive provision protecting against “the deprivation of any rights, privileges, or immunities secured by the Constitution” by any person acting under color of state law, but, as well, the jurisdictional provision authorizing a proceeding for the enforcement of those rights “to be prosecuted in the *582several district or circuit courts of the United States.” 11 Jurisdiction was not independently defined; it was given simply to enforce the substantive rights created by the statute. The two aspects, seemingly, were deemed to coincide.

It has been said that the purpose of the legislation was to enforce the provisions of the Fourteenth, not the Thirteenth, Amendment. District of Columbia v. Carter, 409 U. S., at 423; Lynch v. Household Finance Corp., 405 U. S. 538, 545 (1972); Monroe v. Pape, 365 U. S. 167, 171 (1961). As originally enacted, § 1 of the 1871 Act applied only to action under color of law of any “State.” In 1874, however, Congress, presumably pursuant to its power to “make all needful Rules and Regulations respecting the Territory or other Property belonging to the United States,” granted by the Constitution’s Art. IV, § 3, cl. 2, added, without explanation, the words “or Territory” in the 1874 codification of United States statutes. Rev. Stat. § 1979 (1874). See District of Columbia v. Carter, 409 U. S., at 424 n. 11. The evident aim *583was to insure that all persons residing in the Territories not be denied, by persons acting under color of territorial law, rights guaranteed them by the Constitution and laws of the United States.12

Although one might say that the purpose of Congress was evident, the method chosen to implement this aim was curious and, indeed, somewhat confusing. In the 1874 codification, only the substantive portion (the predecessor of today’s § 1983) of § 1 of the 1871 Act was redesignated as § 1979.13 It became separated from the jurisdictional portion (the predecessor of today’s § 1343 (3)) which appeared as § 563 Twelfth and § 629 Sixteenth (concerning, respectively, the district courts and the circuit courts) of the Revised Statutes. But the words “or Territory” appeared only in § 1979; they did not appear in §§ 563 and 629.

Our question, then, is whether, in separately codifying the provisions and in having this discrepancy between them, Congress intended to restrict federal-court jurisdiction in some way. We conclude that it intended no such restriction. First, as stated above, the common origin of §§ 1983 and 1343 (3) in § 1 of the 1871 Act suggests that the two provisions were meant to be, and are, complementary. Lynch v. Household Finance *584Corp., 405 U. S., at 543 n. 7. There is no indication that Congress intended to prevent federal district and circuit courts from exercising subject-matter jurisdiction of claims of deprivation of rights under color of territorial law if they otherwise had personal jurisdiction of the parties. Second, a contrary interpretation necessarily would lead to the conclusion that persons residing in a Territory were not effectively afforded a federal-court remedy there for a violation of the 1871 Act despite Congress’ obvious intention to afford one. The then existing territorial district courts established by Congress were granted “the same jurisdiction, in all cases arising under the Constitution and laws of the United States, as is vested in the circuit and district courts of the United States.” Rev. Stat. § 1910 (1874) (emphasis added).14 Thus, if the federal district and circuit courts had jurisdiction to redress deprivations only under color of state (but not territorial) law, the territorial courts were likewise so limited. Further, the United States District Courts for the Districts of California and Oregon, and the territorial District Court for Washington possessed jurisdiction over violations of laws extended to the Territory of Alaska. Rev. Stat. § 1957 (1874). Unless the federal courts had jurisdiction to redress deprivations of rights by persons acting under color of territorial law, *585Congress’ explicit extension of the 1871 Act to provide a remedy against persons acting under color of territorial law was only theoretical because no forum existed in which these rights might be enforced.

This conclusion that Congress granted territorial courts jurisdiction to enforce the provisions of § 1979 is strengthened by two additional factors. First, Congress explicitly provided: “The Constitution and all laws of the United States which are not locally inapplicable shall have the same force and effect within all the organized Territories, and in every Territory hereafter organized as elsewhere within the United States.” Rev. Stat. § 1891 (1874). Section 1979, with its reference to Territories was obviously an applicable statute. Second, it was not until the following year that Congress conferred on United States district courts general federal-question jurisdiction.15 Act of Mar. 3, 1875, § 1, 18 Stat. 470, now codified as 28 U. S. C. § 1331 (a). See generally Zwickler v. Koota, 389 U. S. 241, 245-247 *586(1967). Accordingly, unless in 1874 the federal district and circuit courts had jurisdiction to redress deprivations under color of territorial law, Congress, although providing rights and remedies, could be said to have failed to provide a means for their enforcement.

For all these reasons, we conclude that the federal territorial as well as the federal district and circuit courts generally had jurisdiction to redress deprivations of constitutional rights by persons acting under color of territorial law. We turn, then, to the legislation specifically applicable to Puerto Rico.

B. A similar approach was taken by Congress in its establishment of the civil government in Puerto Rico in the exercise of its territorial power under Const., Art. IV, § 3, cl. 2.16 By the Treaty of Paris, 30 Stat. 1754 (1899), Spain ceded Puerto Rico to the United States. 30 Stat. 1755. Shortly thereafter, the Foraker Act, being the Act of April 12, 1900, 31 Stat. 77, became law. This legislation established a civil government for Puerto *587Rico, including provisions for courts. The judicial structure so created consisted of a local court system with a Supreme Court, and, as well, of a Federal District Court.17 The Act, § 34,31 Stat. 84, provided: “The [federal] district court . . . shall have, in addition to the ordinary jurisdiction of district courts of the United States, jurisdiction of all cases cognizant in the circuit courts of the United States.” 18

On its face, this appears to have been a broad grant of jurisdiction similar to that conferred on the United States district courts and comparable to that conferred on the earlier territorial courts. The earlier territorial grants, however, were different. Whereas the Federal District Court for Puerto Rico was to have “the ordinary jurisdiction of district courts of the United States,” the earlier territorial courts had been given explicitly, by Rev. Stat. § 1910 noted above, “the same jurisdiction, in all cases arising under the Constitution and laws of the United States, as is vested in the circuit and district courts of the United States.” One might expect that *588the grant of jurisdiction in the former necessarily encompassed or was the same as the grant of jurisdiction in the latter. Congress, however, was divided over the question whether the Constitution extended to Puerto Rico by its own force or whether Congress possessed the power to withhold from Puerto Ricans the constitutional guarantees available to all persons within the several States and the earlier Territories. See S. Rep. No. 249, 56th Cong., 1st Sess. (1900); H. R. Rep. No. 249, 56th Cong., 1st Sess. (1900).19

The division within Congress was reflected in the legislation governing Puerto Rico. Thus, despite some support for the measure, see S. Rep. No. 249, pp. 12-13, Congress declined to grant citizenship to the inhabitants of Puerto Rico. 33 Cong. Rec. 3690 (1900). And, in contrast to some earlier territorial legislation, Congress did not expressly extend to Puerto Rico the Constitution of the United States or impose on the statutes of Puerto Rico then in effect the condition that they be continued only if consistent with the United States Constitution.20

*589At the same time, however, Congress undoubtedly was aware of the above-mentioned Rev. Stat. § 1891 providing : “The Constitution and all laws of the United States which are not locally inapplicable shall have the same force and effect ... in every Territory hereafter organized as elsewhere within the United States.” Yet no mention of this statute was made in the Foraker Act. In contrast, two years later, Congress made § 1891 expressly inapplicable when it created a civil government for the Territory of the Philippines. Act of July 1, 1902, c. 1369, § 1, 32 Stat. 692.21 Moreover, Congress, by § 14 of the Foraker Act, extended to Puerto Rico “the statutory laws [other than the internal revenue *590laws] of the United States not locally inapplicable,” 31 Stat. 80,22 and Rev. Stat. § 1979, providing remedies for deprivation of rights guaranteed by the Constitution and laws of the United States by persons acting under color of territorial law was at least potentially “applicable.”

This review of the For alter Act and its legislative history leads to several conclusions: Congress was uncertain of its own powers respecting Puerto Rico and of the extent to which the Constitution applied there. At the same time, it recognized, at least implicitly, that the ultimate resolution of these questions was the responsibility of this Court. S. Rep. No. 249, pp. 9-12; H. R. Rep. No. 249, pp. 9-15, 25-28. Thus Congress appears to have left the question of the personal rights to be accorded to the inhabitants of Puerto Rico to orderly development by this Court and to whatever further provision Congress itself might make for them. The grant of jurisdiction to the District Court in Puerto Rico, nevertheless, appeared to be sufficiently broad to permit redress of deprivations of those rights by persons acting under color of territorial law. See Insular Police Comm’n v. Lopez, 160 F. 2d 673, 676-677 (CA1), cert. denied, 331 U. S. 855 (1947). Nothing in the language of § 34 of the Foraker Act precluded the grant of ju*591risdiction accorded the earlier territorial courts by Rev. Stat. § 1910, and its language, containing no limitations, cautions us against reading into it an exception not supported by persuasive evidence in the legislative history.

Subsequent legislation respecting Puerto Rico tends to support the conclusion that uncertainty over the application of the Constitution did not lead Congress to deprive the inhabitants of Puerto Rico of a federal forum for vindication of whatever rights did exist. In the Organic Act of 1917, sometimes known as the Jones Act, 39 Stat. 951, Congress made more explicit the jurisdiction of the Federal District Court by according it “jurisdiction of all cases cognizable in the district courts of the United States,” § 41, 39 Stat. 965; generally granted Puerto Rico citizens United States citizenship, § 5, 39 Stat. 953; and codified for Puerto Rico a bill of rights, § 2, 39 Stat. 951. This bill of rights, which remained in effect until 1952, provided Puerto Ricans with nearly all the personal guarantees found in the United States Constitution.23 The very first provision, for example, read: “That no law shall be enacted in Porto Rico which shall deprive any person of life, liberty, or property without due process of law, or deny to any person therein the equal protection of the laws.” These words are almost identical with the language of the Fourteenth Amendment; and when Congress selected them, it must have done so with the Fourteenth Amendment *592in mind and with a view to further development by this Court of the doctrines embodied in it. See Kepner v. United States, 195 U. S. 100, 124 (1904). In its passage of the Jones Act, Congress clearly set the stage for the federal court in Puerto Rico to enforce the provisions of § 1983’s predecessor (Rev. Stat. § 1979) which prohibited the deprivation “under color of any statute, ordinance, regulation, custom, or usage, of any . . . Territory ... of any rights, privileges, or immunities secured by the Constitution and laws.” See Munoz v. Porto Rico Ry. Light & Power Co., 83 F. 2d 262, 26A-266 (CA1), cert. denied, 298 U. S. 689 (1936).

The jurisdictional provision of the Act, referring to “all cases cognizable in the district courts of the United States,” remained in effect until 1948. At that time Congress, in the course of a major revision of the Judicial Code, placed the nonterritorial jurisdiction of the District Court of Puerto Rico, as well as the District Court of Hawaii, squarely within Title 28 of the United States Code. It provided: “Puerto Rico constitutes one judicial district.” Act of June 25, 1948, c. 646, § 119, 62 Stat. 889. The stated reason for this change was that “Hawaii and Puerto Rico are included as judicial districts of the United States, since in matters of jurisdiction, powers, and procedure, they are in all respects equal to other United States district courts.” H. R. Rep. No. 308, 80th Cong., 1st Sess., 6 (1947). This confirms our conclusion that until the establishment of the Commonwealth, the Federal District Court in Puerto Rico had the same jurisdiction to enforce the provisions of 42 U. S. C. § 1983 as that conferred by 28 U. S. C. § 1343 (3) and its predecessor statutes on the United States district courts in the several States. See Miranda v. United States, 255 F. 2d 9 (CA1 1958); Insular Police Comm’n v. Lopez, supra.

Only two years later, Congress responded to demands *593for greater autonomy 24 for Puerto Rico with the Act of July 3, 1950; c. 446, 64 Stat. 319. This legislation, offered, in the “nature of a compact” to “the people of Puerto Rico,” § 1, 48 U. S. C. § 731b, authorized them to draft their own constitution which, however, “shall provide a republican form of government and shall include a bill of rights,” § 2, 48 U. S. C. § 731c. The proposed constitution thereafter submitted declared that it was drafted “within our union with the United States of America,” and that among the “determining factors in our life” were considered “our citizenship of the United States of America” and “our loyalty to the principles of the Federal Constitution.” Preamble of the Constitution of Puerto Rico, 1 P. R. Laws Ann. p. 207 (1965). See note following 48 U. S. C. § 731d. Congress approved the proposed constitution after adding, among other things, a condition that any amendment or revision of the document be consistent with “the applicable provisions of the Constitution of the United States.” 66 Stat. 327.25 The condition was accepted, the compact *594became effective, and Puerto Rico assumed “Commonwealth” status. This resulted in the repeal of numerous provisions of the Organic Act of 1917, including the bill of rights that Act contained. Act of July 3, 1950, c. 446, § 5, 64 Stat. 320. The remainder became known as the Puerto Rican Federal Relations Act. § 4, 64 Stat. 319.

The question then arises whether Congress, by entering into the compact, intended to repeal by implication the jurisdiction of the Federal District Court of Puerto Rico to enforce 42 U. S. C. § 1983. We think not. As was observed in Calero-Toledo v. Pearson Yacht Leasing Co., 416 U. S., at 671, the purpose of Congress in the 1950 and 1952 legislation was to accord to Puerto Rico the degree of autonomy and independence normally associated with States of the Union, and accordingly, Puerto Rico “now ‘elects its Governor and legislature; appoints its judges, all cabinet officials, and lesser officials in the executive branch; sets its own educational policies; determines its own budget; and amends its own civil and criminal codq.’ ” See generally Leibowitz, The Applicability of Federal Law to the Commonwealth of Puerto Rico, 56 Geo. L. J. 219, 221 (1967); Magruder, The Commonwealth Status of Puerto Rico, 15 U. Pitt. L. Rev. 1 (1953); Americana of Puerto Rico, Inc. v. Kaplus, 368 F. 2d 431 (CA3 1966), cert. denied, 386 U. S. 943 (1967). More importantly, the provisions relating to the jurisdiction of a Federal District Court in Puerto Rico were left undisturbed, and there is no evidence in the legislative history that would support a determination that Congress intended such a departure.26 In the *595absence of a change in the language of the jurisdictional provision or of affirmative evidence in the legislative history, we are unwilling to read into the 1952 legislation a restriction of the jurisdiction of the Federal District Court.

C. Our conclusion not to attribute to Congress an inclination to leave the protection of federal rights exclusively to the local Puerto Rico courts is supported by District of Columbia v. Carter, 409 U. S. 418 (1973). There the Court held that the District was neither a State nor a Territory within the meaning of 42 U. S. C. § 1983. The District, it was observed, occupies a unique status within our system of government. It is the seat of the National Government, and, at the time the Civil Rights Act of 1871 was enacted, Congress exercised plenary power over its activities. These geographical and political considerations, as well as “the absence of any indication in the language, purposes, or history of § 1983 of a legislative intent to include the District within the scope of its coverage,” supported the Court’s conclusion. 409 U. S., at 432.

Appellants, however, focus upon the characterization of the District as “sui generis in our governmental structure,” ibid., and argue that because the Commonwealth of Puerto Rico is also sui generis, the conduct of persons acting under color of Commonwealth law is similarly *596exempted from scrutiny under § 1983.27 We readily concede that Puerto Rico occupies a relationship to the United States that has no parallel in our history, but we think that it does not follow that Congress intended to relinquish federal enforcement of § 1983 by restricting the jurisdiction of the Federal District Court in Puerto Rico. It was observed in Carter, 409 U. S., at 427, that Congress, in enacting the civil rights legislation with which we are concerned, recognized that it “had neither the means nor the authority to exert any direct control, on a day-to-day basis, over the actions of state officials,” and that the “solution chosen was to involve the federal judiciary.” Congress similarly lacked effective control over actions taken by territorial officials, although its authority to govern was plenary.28 The same practical *597limitations on Congress’ effectiveness to protect the federally guaranteed rights of the inhabitants of Puerto Rico existed from the time of its cession and, after 1952, when Congress relinquished its control over the organization of the local affairs of the island and granted Puerto Rico a measure of autonomy comparable to that possessed by the States, the need for federal protection of federal rights was not thereby lessened. Finally, § 1983, by its terms, applies to Territories; Puerto Rico, but not the District of Columbia, obviously was one of these. Whether Puerto Rico is now considered a Territory or a State, for purposes of the specific question before us, makes little difference because each is included within § 1983 and, therefore, 28 U. S. C. § 1343 (3).

It fallows that the United States District Court for the District of Puerto Rico has jurisdiction under 28 U. S. C. § 1343 (3) to enforce the provisions of 42 U. S. C. § 1983.

Ill

Appellants, however, argue that the District Court should have abstained from reaching the merits of the constitutional claim. Fornaris v. Ridge Tool Co., 400 U. S. 41 (1970), is cited as an example of abstention in a Puerto Rico context. We conclude that the District Court correctly determined that abstention was unnecessary. The case presents no novel question concerning the judicially created abstention doctrine; it requires, instead, only the application of settled principles reviewed just last Term in Harris County Comm’rs Court v. Moore, 420 U. S. 77 (1975).

Appellants urge that abstention was appropriate for *598two reasons. First, it is said that § 689 should be construed by the commonwealth courts in the light of § 1483 of the Civil Code, P. R. Laws Ann., Tit. 31, § 4124 (1968). This provision imposes liability on a contractor for defective construction of a building. We fail to see, however, how § 4124 in any way could affect the interpretation of § 689 which imposes, with the exceptions that have been noted, a requirement of citizenship for the licensing of an engineer.

Appellants’ second argument is that the commonwealth courts should be permitted to adjudicate the validity of the citizenship requirement in the light of §§ 1 and 7 of Art. II of the Puerto Rico Constitution. 1 P. R. Laws Ann., Const., Art. II, §§ 1, 7 (1965). Section 1 provides: “No discrimination shall be made on account of race, color, sex, birth, social origin or condition, or political or religious ideas.” Section 7 provides: “No person in Puerto Rico shall be denied the equal protection of the laws.” These constitutional provisions are not so interrelated with § 689 that it may be said, as in Harris County, that the law of the Commonwealth is ambiguous. Rather, the abstention issue seems clearly controlled by Wisconsin v. Constantineau, 400 U. S. 433 (1971), where, as it was said in Harris County, 420 U. S., at 8A-85, n. 8, “we declined to order abstention where the federal due process claim was not complicated by an unresolved state-law question, even though the plaintiffs might have sought relief under a similar provision of the state constitution.” Indeed, to hold that abstention is required because § 689 might conflict with the cited broad and sweeping constitutional provisions, would convert abstention from an exception into a general rule.29

*599IV

This takes us, then, to the particular Puerto Rico statute before us. Does Puerto Rico’s prohibition against an alien’s engaging in the private practice of engineering deprive the appellee aliens of “any rights, privileges, or immunities secured by the Constitution and laws,” within the meaning of 42 U. S. C. § 1983?

A. The Court’s decisions respecting the rights of the inhabitants of Puerto Rico have been neither unambiguous nor exactly uniform. The nature of this country’s relationship to Puerto Rico was vigorously debated within the Court as well as within the Congress.30 See *600Coudert, The Evolution of the Doctrine of Territorial Incorporation, 26 Col. L. Rev. 823 (1926). It is clear now, however, that the protections accorded by either the Due Process Clause of the Fifth Amendment or the Due Process and Equal Protection Clauses of the Fourteenth Amendment apply to residents of Puerto Rico. The Court recognized the applicability of these guarantees as long ago as its decisions in Downes v. Bidwell, 182 U. S. 244, 283-284 (1901), and Balzac v. Porto Rico, 258 U. S. 298, 312-313 (1922). The principle was reaffirmed and strengthened in Reid v. Covert, 354 U. S. 1 (1957),31 and then again in Calero-Toledo, *601416 U. S. 663 (1974), where we held that inhabitants of Puerto Rico are protected, under either the Fifth Amendment or the Fourteenth, from the official taking of property without due process of law.

The Court, however, thus far has declined to say whether it is the Fifth Amendment or the Fourteenth which provides the protection.32 Calero-Toledo, 416 U. S., at 668-669, n. 5. Once again, we need not resolve that precise question because, irrespective of which Amendment applies, the statutory restriction on the ability of aliens to engage in the otherwise lawful private practice of civil engineering is plainly unconstitutional. If the Fourteenth Amendment is applicable, the Equal Protection Clause nullifies the statutory exclusion. If, on the other hand, it is the Fifth Amendment and its Due Process Clause that apply, the statute’s discrimination is so egregious that it falls within the rule of Bolling v. Sharpe, 347 U. S. 497, 499 (1954).33 See also Schneider v. Rusk, 377 U. S. 163, 168 (1964).

B. In examining the validity of Puerto Rico’s virtually complete ban on the private practice of civil engineering by aliens, we apply the standards of our recent decisions in Graham v. Richardson, 403 U. S. 365 (1971); Sugar*602man v. Dougall, 413 U. S. 634 (1973); and In re Griffiths, 413 U. S. 717 (1973). These cases establish that state classifications based on alienage are subject to “strict judicial scrutiny.” Graham v. Richardson, 403 U. S., at 376. Statutes containing classifications of this kind will be upheld only if the State or Territory imposing them is able to satisfy the burden of demonstrating “that its purpose or interest is both constitutionally permissible and substantial, and that its use of the classification is 'necessary ... to the accomplishment’ of its purpose or the safeguarding of its interest.” In re Griffiths, 413 U. S., at 721-722 (footnotes omitted). These principles are applicable to the Puerto Rico statute now under consideration.

The underpinnings of the Court’s constitutional decisions defining the circumstances under which state and local governments may favor citizens of this country by denying lawfully admitted aliens equal rights and opportunities have been two. The first, based squarely on the concepts embodied in the Equal Protection Clause of the Fourteenth Amendment and in the Due Process Clause of the Fifth Amendment, recognizes that “[a]liens as a class are a prime example of a 'discrete and insular’ minority ... for whom . . . heightened judicial solicitude is appropriate.” Graham v. Richardson, 403 U. S., at 372. See also San Antonio School Dist. v. Rodriguez, 411 U. S. 1, 29 (1973); Sugarman v. Dougall, 413 U. S., at 642. The second, grounded in the Supremacy Clause, Const., Art. VI, cl. 2, and in the naturalization power, Art. I, § 8, cl. 4, recognizes the Federal Government’s primary responsibility in the field of immigration and naturalization. See, e. g., Hines v. Davidowitz, 312 U. S. 52, 66 (1941); Truax v. Raich, 239 U. S. 33, 42 (1915). See also Graham v. Richardson, 403 U. S., at 378; Takahashi v. Fish & Game Comm’n, 334 U. S. 410, 419 (1948).

*603Official discrimination against lawfully admitted aliens traditionally has taken several forms. Aliens have been prohibited from enjoying public resources or receiving public benefits on the same basis as citizens. See Graham v. Richardson, supra; Takahashi v. Fish & Game Comm’n, supra. Aliens have been excluded from public employment. Sugarman v. Dougall, supra. See M. Konvitz, The Alien and the Asiatic in American Law, c. 6 (1946). And aliens have been restricted from engaging in private enterprises and occupations that are otherwise lawful. See In re Griffiths, supra; Truax v. Raich, supra; Yick Wo v. Hopkins, 118 U. S. 356, 369 (1886).34

The present Puerto Rico statute, of course, falls into the last category. It is with respect to this kind of discrimination that the States have had the greatest difficulty in persuading this Court that their interests are substantial and constitutionally permissible, and that the discrimination is necessary for the safeguarding of those interests. Thus, in Yick Wo v. Hopkins the Court struck down an ordinance that was administered so as to exclude aliens from pursuing the lawful occupation of a laundry. In Truax v. Raich the Court invalidated a state statute that required a private employer, having five or more workers, to employ at least 80% qualified electors or native-born citizens. And in In re Griffiths a state statutory requirement prescribing United States citizenship as a condition for engaging in the practice of law was held unconstitutional. But see Ohio ex rel. Clarke v. Deckebach, 274 U. S. 392 (1927).

*604The reason for this solicitude with respect to an alien’s engaging in an otherwise lawful occupation is apparent:

“It requires no argument to show that the right to work for a living in the common occupations of the community is of the very essence of the personal freedom and opportunity that it was the purpose of the [Fourteenth] Amendment to secure. If this could be refused solely upon the ground of race or nationality, the prohibition of the denial to any person of the equal protection of the laws would be a barren form of words.” Truax v. Raich, 239 U. S., at 41 (citations omitted).

It is true that in Truax the Court drew a distinction between discrimination against aliens in private lawful occupations and discrimination against them where, it might be said, the State has a special interest in affording protection to its own citizens. Id., at 39^40. That distinction, however, is no longer so sharp as it then was. Recently the Court has taken a more restrictive view of the powers of a State to discriminate against non-citizens with respect to public employment, compare Crane v. New York, 239 U. S. 195 (1915), aff’g People v. Crane, 214 N. Y. 154, 108 N. E. 427, and Heim v. McCall, 239 U. S. 175 (1915), with Sugarman v. Dougall, supra; and with respect to the distribution of public funds and the allocation of public resources, compare McCready v. Virginia, 94 U. S. 391 (1877), and Patsone v. Pennsylvania, 232 U. S. 138 (1914), with Graham v. Richardson, supra, and Takahashi v. Fish & Game Comm’n, supra.

We do not suggest, however, that a State, Territory, or local government, or certainly the Federal Government, may not be permitted some discretion in determining the circumstances under which it will employ aliens or whether aliens may receive public benefits or partake *605of public resources on the same basis as citizens. In each case, the governmental interest claimed to justify the discrimination is to be carefully examined in order to determine whether that interest is legitimate and substantial, and inquiry must be made whether the means adopted to achieve the goal are necessary and precisely drawn.

In the present case the appellants have offered three justifications for Puerto Rico's almost total ban on aliens’ engaging in the private practice of engineering: The first is to prevent the "uncontrolled” influx of Spanish-speaking aliens into the field in Puerto Rico. The second is to raise the prevailing low standard of living. The third is to provide the client of a civil engineer an assurance of financial accountability if a building for which the engineer is responsible collapses within 10 years of construction. P. R. Laws Ann., Tit, 31, § 4124 (1968).

The first justification amounts to little more than an assertion that discrimination may be justified by a desire to discriminate. This interest is unpersuasive on its face. It is also at odds with the Federal Government’s primary power and responsibility for the regulation of immigration. Once an alien is lawfully admitted, a State may not justify the restriction of the alien’s liberty on the ground that it wishes to control the impact or effect of federal immigration laws. Cf. DeCanas v. Bica, 424 U. S. 351 (1976).

Although the second broad justification proffered by the appellants has elements of substance and legitimacy, the means drawn to achieve the end are neither necessary nor precise. What the Commonwealth has done by its statute is to require private employers and contractors to hire only engineers who are American citizens. This end was held impermissible over 50 years ago in Truax v. Raich, supra. To uphold the statute on the basis of broad economic justification of this kind would permit *606any State to bar the employment of aliens in any or all lawful occupations.

Finally, the asserted purpose to assure responsibility for negligent workmanship sweeps too broadly. United States citizenship is not a guarantee that a civil engineer will continue to reside in Puerto Rico or even in the United States, and it bears no particular or rational relationship to skill, competence, or financial responsibility. See Sugarman v. Dougall, 413 U. S., at 645; In re Griffiths, 413 U. S., at 724. Puerto Rico has available to it other ample tools to achieve the goal of an engineer’s financial responsibility without indiscriminately prohibiting the private practice of civil engineering by a class of otherwise qualified professionals.

The judgments of the District Court are affirmed.

It is so ordered.

Mr. Justice Stevens took no part in the consideration or decision of this case.

dissenting in part.

I agree with the Court’s conclusion that the United States District Court for the District of Puerto Rico had jurisdiction of appellees’ claim under 28 U. S. C. § 1343 (3), and that it was not obligated to abstain from reaching the merits of that claim. I believe that I have some understanding of the difficulties which the Court necessarily encounters in then determining whether either the Fifth Amendment or the Fourteenth Amendment to the United States Constitution applies to Puerto Rico. But without attempting to recapitulate the doctrine of the cases from Downes v. Bidwell, 182 U. S. 244 (1901), to Calero-Toledo v. Pearson Yacht Leasing Co., 416 U. S. 663 (1974), I do not think the inquiry lends itself to the facile “either-or” answer upon which the Court ultimately settles,

*607The Fourteenth Amendment is by its terms applicable to States: Puerto Rico is not a State. Doubtless constitutional inquiries shrouded as this one is in both history and case law cannot be definitively answered so simply as this, but I would be inclined to reject the claim that the Fourteenth Amendment is applicable to Puerto Rico until a case sufficiently strong to overcome this “plain meaning” obstacle, found in the language of the Amendment itself, is made out.*

The Fifth Amendment, of course, applies to Congress, and had this statute been enacted by Congress it would be subject to the strictures of the Fifth Amendment. But just as certainly it was not enacted by Congress, but by the Legislature of Puerto Rico. I could perhaps understand in this regard a theory that under the Foraker Act, which reserved to Congress the right to annul laws of the Puerto Rican Legislature with which it disagreed, see ante, at 586 n. 16, that legislature should be treated as the delegate of Congress equally subject to the strictures of the Fifth Amendment. But any such theory would, of course, face very substantial obstacles in view of the fact that Congress subsequently provided in the Organic Act of 1917 a bill of rights, giving Puerto Ricans “nearly all the personal guarantees found in the United States Constitution.” Ante, at 591 (emphasis supplied).

If the constitutional limitations expressly directed to Congress, such as the Fifth Amendment, also directly restrict the Puerto Rican Legislature by virtue of its being a delegate of Congress, it would not only have been superfluous for Congress to provide an additional bill of *608rights; it would have been quite impossible for it to endow its delegate with more power to disregard individual liberties than it itself may possess. I would thus find it extremely difficult to see how constitutional limitations upon the power of Congress may be thought to apply ex proprio vigore to the power of the Puerto Rican Legislature. Moreover, following the passage of the Act of July 3, 1950, and Puerto Rico’s acceptance of Commonwealth status, see ante, at 593-594,1 would have thought that the only restrictions upon the elected Legislature of Puerto Rico were those embodied in the Constitution enacted as a condition of assuming that status or directly imposed by Congress by statute.

In short, I am not nearly as certain as the Court appears to be that either the Fifth Amendment or the Fourteenth Amendment must govern the acts of the Legislature of Puerto Rico. It seems to me it is quite possible that neither provision operates as a direct limitation upon the authority of that elected body. Even if I am wrong in this, I would not have thought it as easy as does the Court to avoid more focused inquiry in this case into which provision may be applicable. For even if a State could not, consistent with the Equal Protection Clause of the Fourteenth Amendment, pass the statute challenged by appellees, it surely does not follow that the Fifth Amendment’s due process limitation upon the exercise of federal authority requires an identical conclusion. See Hampton v. Mow Sun Wong, ante, at 100-101. For if for some reason it were to be concluded that the restrictions placed upon the Federal Government were somehow directly applicable to the actions of appellants, it would seem that they would be able equivalently to assert whatever additional authority that Government possesses with regard to aliens. Indeed, rejection of this approach would raise an even more *609difficult question: Why should a restriction upon the authority of the Government of the United States, which may be thought of as granting concomitant rights to United States citizens, have any bearing upon how the people of a Territory of the United States may deal with aliens within their Territory?

If the answers to these questions were dispositive of my vote in this case, I would feel compelled to explore them in much more detail than does the Court today. But even if I were to conclude that one part of the Court’s either/or assumption was correct, I could not agree with the result which it believes is compelled by that assumption. I do not agree either that the statute in question violates the Equal Protection Clause of the Fourteenth Amendment, for the reasons stated in my dissent in Sugarman v. Dougall, 413 U. S. 634, 649 (1973), or that if the statute were subject to the limitations of the Fifth Amendment, it is infirm by reason of their application. Hampton v. Mow Sun Wong, ante, p. 117 (RehNQTjIST, J., dissenting). I would therefore reverse the decision of the District Court.