Justice Marshall
delivered the opinion of the Court.
In this case, we address the question whether federal law pre-empts a state tax imposed on the gross receipts that a non-Indian construction company receives from a tribal school board for the construction of a school for Indian children on the reservation. The New Mexico Court of Appeals held that the gross receipts tax imposed by the State of New Mexico was permissible. Because the decision below is inconsistent with White Mountain Apache Tribe v. Bracker, 448 U. S. 136 (1980) (White Mountain), we reverse.
I
Approximately 2,000 members of the Ramah Navajo Chapter of the Navajo Indian Tribe live on tribal trust and allotment lands located in west central New Mexico. Ramah Navajo children attended a small public high school near the reservation until the State closed this facility in 1968. Because there were no other public high schools reasonably close to the reservation, the Ramah Navajo children were forced either to abandon their high school education or to attend federal Indian boarding schools far from the reservation. In 1970, the Ramah Navajo Chapter exercised its authority under Navajo Tribal Code, Title 10, §51 (1969), and established its own school board in order to remedy this situation. Appellant Ramah Navajo School Board, Inc. (the Board), was organized as a nonprofit corporation to be operated exclusively by members of the Ramah Navajo Chapter. The Board is a Navajo “tribal organization” within the meaning of 25 U. S. C. §450b(c), 88 Stat. 2204. With funds provided by the federal Bureau of Indian Affairs (BIA) and the Navajo Indian Tribe, the Board operated a school in the abandoned public school facility, thus creating the first independent Indian school in modern times.
In 1972, the Board successfully solicited from Congress funds for the design of new school facilities. Pub. L. 92-369, 86 Stat. 510. The Board then contracted with the BIA for the design of the new school and hired an architect. In 1974, the Board contracted with the BIA for the actual construction of the new school to be built on reservation land. Funding for the construction of this facility was provided by a series of congressional appropriations specifically earmarked for this purpose. The contract specified that the Board was the design and building contractor for the project, but that the Board could subcontract the actual construction work to third parties. The contract further provided that any subcontracting agreement would have to include certain clauses governing pricing, wages, bonding, and the like, and that it must be approved by the BIA.
The Board then solicited bids from area building contractors for the construction of the school, and received bids from two non-Indian firms. Each firm included the state gross receipts tax as a cost of construction in their bids, although the tax was not itemized separately. Appellant Lembke Construction Co. (Lembke) was the low bidder and was awarded the contract. The contract between the Board and Lembke provides that Lembke is to pay all “taxes required by law.” Lembke began construction of the school facilities in 1974 and continued this work for over five years. During that time, Lembke paid the gross receipts tax and, pursuant to standard industry practice, was reimbursed by the Board for the full amount paid. Before the second contract between Lembke and the Board was executed in 1977, a clause was inserted into the contract recognizing that the Board could litigate the validity of this tax and was entitled to any refund.
Both Lembke and the Board protested the imposition of the gross receipts tax. In 1978, after exhausting administrative remedies, they filed this refund action against appellee New Mexico Bureau of Revenue in the New Mexico District Court. At the time of trial, the parties stipulated that the Board had reimbursed Lembke for tax payments of $232,264.38 and that the Board would receive any refund that might be awarded.
The trial court entered judgment for the State Bureau of Revenue. After noting that the “legal incidence” of the tax-fell on the non-Indian construction firm, the court rejected appellants’ arguments that the tax was pre-empted by comprehensive federal regulation and that it imposed an impermissible burden on tribal sovereignty. The Court of Appeals for the State of New Mexico affirmed. 95 N. M. 708, 625 P. 2d 1225 (1980). Although acknowledging that the economic burden of the tax fell on the Board, the Court of Appeals concluded that the tax was not preempted by federal law and that it did not unlawfully burden tribal sovereignty. The Board filed a petition for rehearing in light of this Court’s intervening decisions in White Mountain, supra, and Central Machinery Co. v. Arizona State Tax Comm’n, 448 U. S. 160 (1980). The Court of Appeals denied the petition, stating only that this case did not involve either “a comprehensive or pervasive scheme of federal regulation” or “federal regulation similar to the Indian trader statutes.” App. to Juris. Statement 36. After initially granting discretionary review, the New Mexico Supreme Court quashed the writ as improvidently granted. 96 N. M. 17, 627 P. 2d 412 (1981). We noted probable jurisdiction. 454 U. S. 1079 (1981).
II
In recent years, this Court has often confronted the difficult problem of reconciling “the plenary power of the States over residents within their borders with the semi-autonomous status of Indians living on tribal reservations.” McClanahan v. Arizona State Tax Comm’n, 411 U. S. 164, 165 (1973). Although there is no definitive formula for resolving the question whether a State may exercise its authority over tribal members or reservation activities, we have recently identified the relevant federal, tribal, and state interests to be considered in determining whether a particular exercise of state authority violates federal law. See White Mountain, 448 U. S., at 141-145.
A
In White Mountain, we recognized that the federal and tribal interests arise from the broad power of Congress to regulate tribal affairs under the Indian Commerce Clause, Art. I, § 8, cl. 3, and from the semi-autonomous status of Indian tribes. 448 U. S., at 142. These interests tend to erect two “independent but related” barriers to the exercise of state authority over commercial activity on an Indian reservation: state authority may be pre-empted by federal law, or it may interfere with the tribe’s ability to exercise its sovereign functions. Ibid, (citing, inter alia, Warren Trading Post Co. v. Arizona Tax Comm’n, 380 U. S. 685 (1965); McClanahan v. Arizona State Tax Comm’n, supra; and Williams v. Lee, 358 U. S. 217 (1959)). As we explained in White Mountain:
“The two barriers are independent because either, standing alone, can be a sufficient basis for holding state law inapplicable to activity undertaken on the reservation or by tribal members. They are related, however, in two important ways. The right of tribal self-government is ultimately dependent on and subject to the broad power of Congress. Even so, traditional notions of Indian self-government are so deeply engrained in our jurisprudence that they have provided an important ‘backdrop,’ . . . against which vague or ambiguous federal enactments must always be measured.” 448 U. S., at 143 (quoting McClanahan v. Arizona State Tax Comm’n, supra, at 172).
The State’s interest in exercising its regulatory authority over the activity in question must be examined and given appropriate weight. Pre-emption analysis in this area is not controlled by “mechanical or absolute conceptions of state or tribal sovereignty”; it requires a particularized examination of the relevant state, federal, and tribal interests. 448 U. S., at 145. The question whether federal law, which reflects the related federal and tribal interests, pre-empts the State’s exercise of its regulatory authority is not controlled by standards of pre-emption developed in other areas. Id., at 143-144. Instead, the traditional notions of tribal sovereignty, and the recognition and encouragement of this sovereignty in congressional Acts promoting tribal independence and economic development, inform the pre-emption analysis that governs this inquiry. See id., at 143, and n. 10. Relevant federal statutes and treaties must be examined in light of “the broad policies that underlie them and the notions of sovereignty that have developed from historical traditions of tribal independence.” Id., at 144-145. As a result, ambiguities in federal law should be construed generously, and federal pre-emption is not limited to those situations where Congress has explicitly announced an intention to pre-empt state activity. Id., at 143-144, 150-151.
In White Mountain, we applied these principles and held that federal law pre-empted application of the state motor carrier license and use fuel taxes to a non-Indian logging company’s activity on tribal land. We found the federal regulatory scheme for harvesting Indian timber to be so pervasive that it precluded the imposition of additional burdens by the relevant state taxes. Id., at 148. The Secretary of the Interior (Secretary) had promulgated detailed regulations for developing “‘Indian forests by the Indian people for the purpose of promoting self-sustaining communities.’” Id., at 147 (quoting 25 CFR § 141.3(a)(3) (1979)). Under these regulations, the BIA was involved in virtually every aspect of the production and marketing of Indian timber. 448 U. S., at 145-148. In particular, the Secretary and the BIA extensively regulated the contractual relationship between the Indians and the non-Indians working on the reservation: they established the bidding procedure, set mandatory terms to be included in every contract, and required that all contracts be approved by the Secretary. Id., at 147.
We found that the state taxes in question would “threaten the overriding federal objective of guaranteeing Indians that they will ‘receive . . . the benefit of whatever profit [the forest] is capable of yielding. .. .’ ” Id., at 149 (quoting 25 CFR § 141.3(a)(3) (1979)). We concluded that the imposition of state taxes would also undermine the Secretary’s ability to carry out his obligations to set fees and rates for the harvesting and sale of the timber, and it would impede the “Tribe’s ability to comply with the sustained-yield management policies imposed by federal law.” 448 U. S., at 149-150. Balanced against this intrusion into the federal scheme, the State asserted only “a general desire to raise revenue” as its justification for imposing the taxes. Id., at 150. In this context, this interest is insufficient to justify the State’s intrusion into a sphere so heavily regulated by the Federal Government. Ibid.
B
This case is indistinguishable in all relevant respects from White Mountain. Federal regulation of the construction and financing of Indian educational institutions is both comprehensive and pervasive. The Federal Government’s concern with the education of Indian children can be traced back to the first treaties between the United States and the Navajo Tribe. Since that time, Congress has enacted numerous statutes empowering the BIA to provide for Indian education both on and off the reservation. See, e. g., Snyder Act, 42 Stat. 208 (1921), 25 U. S. C. §13; Johnson-O’Malley Act, 48 Stat. 596 (1934), 25 U. S. C. §452 et seq.; Navajo-Hopi Rehabilitation Act, 64 Stat. 44 (1950), 25 U. S. C. §631 et seq.; Indian Self-Determination and Education Assistance Act, 88 Stat. 2203 (1975), 25 U. S. C. §450 et seq. (Self-Determination Act). Although the early focus of the federal efforts in this area concentrated on providing federal or state educational facilities for Indian children, in the early 1970’s the federal policy shifted toward encouraging the development of Indian-controlled institutions on the reservation. See 6 Weekly Comp, of Pres. Doc. 894, 899-900 (1970) (Message of President Nixon).
This federal policy has been codified in the Indian Financing Act of 1974, 88 Stat. 77, 25 U. S. C. §1451 et seq., and most notably in the Self-Determination Act. The Self-Determination Act declares that a “major national goal of the United States is to provide the quantity and quality of educational services and opportunities which will permit Indian children to compete and excel in the life areas of their choice, and to achieve the measure of self-determination essential to their social and economic well-being.” 88 Stat. 2203, as set forth in 25 U. S. C. § 450a(c). In achieving this goal, Congress expressly recognized that “parental and community control of the educational process is of crucial importance to the Indian people.” 88 Stat. 2203, as set forth in 25 U. S. C. § 450(b)(3).
Section 450k empowers the Secretary to promulgate regulations to accomplish the purposes of the Act. 88 Stat. 2212, 25 U. S. C. §450k. Pursuant to this authority, the Secretary has promulgated detailed and comprehensive regulations respecting “school construction for previously private schools now controlled and operated by tribes or tribally approved Indian organizations.” 25 CFR §274.1 (1981). Under these regulations, the BIA has wide-ranging authority to monitor and review the subcontracting agreements between the Indian organization, which is viewed as the ' general contractor, and the non-Indian firm that actually constructs the facilities. See 25 CFR §274.2 (1981). Specifically, the BIA must conduct preliminary on-site inspections, and prepare cost estimates for the project in cooperation with the tribal organization. 25 CFR § 274.22 (1981). The Board must approve any architectural or engineering agreements executed in connection with the project. 25 CFR § 274.32(c) (1981). In addition, the regulations empower the BIA to require that all subcontracting agreements contain certain terms, ranging from clauses relating to bonding and pay scales, 41 CFR §14H-70.632 (1981), to preferential treatment for Indian workers. 25 CFR §274.38 (1981). Finally, to ensure that the Tribe is fulfilling its statutory obligations, the regulations require the tribal organization to maintain records for the Secretary’s inspection. 25 CFR §274.41 (1981).
This detailed regulatory scheme governing the construction of autonomous Indian educational facilities is at least as comprehensive as the federal scheme found to be pre-emptive in White Mountain. The direction and supervision provided by the Federal Government for the construction of Indian schools leave no room for the additional burden sought to be imposed by the State through its taxation of the gross receipts paid to Lembke by the Board. This burden, although nominally falling on the non-Indian contractor, necessarily impedes the clearly expressed federal interest in promoting the “quality and quantity” of educational opportunities for Indians by depleting the funds available for the construction of Indian schools.
The Bureau of Revenue argues that imposition of the state tax is not pre-empted because the federal statutes and regulations do not specifically express the intention to pre-empt this exercise of state authority. This argument is clearly foreclosed by our precedents. In White Mountain we flatly rejected a similar argument. 448 U. S., at 150-151 (citing Warren Trading Post Co. v. Arizona Tax Comm’n, 380 U. S. 685 (1965); Williams v. Lee, 358 U. S. 217 (1959); and Kennerly v. District Court of Montana, 400 U. S. 423 (1971)). There is nothing unique in the nature of a gross receipts tax or in the federal laws governing the development of tribal self-sufficiency in the area of education that requires a different analysis.
In this case, the State does not seek to assess its tax in return for the governmental functions it provides to those who must bear the burden of paying this tax. Having declined to take any responsibility for the education of these Indian children, the State is precluded from imposing an additional burden on the comprehensive federal scheme intended to provide this education — a scheme which has “left the State with no duties or responsibilities.” Warren Trading Post Co. v. Arizona Tax Comm’n, supra, at 691. Nor has the State asserted any specific, legitimate regulatory interest to justify the imposition of its gross receipts tax. The only arguably specific interest advanced by the State is that it provides services to Lembke for its activities off the reservation. This interest, however, is not a legitimate justification for a tax whose ultimate burden falls on the tribal organization. Furthermore, although the State may confer substantial benefits on Lembke as a state contractor, we fail to see how these benefits can justify a tax imposed on the construction of school facilities on tribal lands pursuant to a contract between the tribal organization and the non-Indian contracting firm. The New Mexico gross receipts tax is intended to compensate the State for granting “the privilege of engaging in business.” N. M. Stat. Ann. §§ 7 — 9—3(F) and 7-9-4(A) (1980). New Mexico has not explained the source of its power to levy such a tax in this case where the “privilege of doing business” on an Indian reservation is exclusively bestowed by the Federal Government.
The State’s ultimate justification for imposing this tax amounts to nothing more than a general desire to increase revenues. This purpose, as we held in White Mountain, 448 U. S., at 150, is insufficient to justify the additional burdens imposed by the tax on the comprehensive federal scheme regulating the creation and maintenance of educational opportunities for Indian children and on the express federal policy of encouraging Indian self-sufficiency in the area of education. This regulatory scheme precludes any state tax that “stands as an obstacle to the accomplishment of the full purposes and objectives of Congress.” Hines v. Davidowitz, 312 U. S. 52, 67 (1941).
C
The Solicitor General, in an amicus brief filed on behalf of the United States, suggests that we modify our pre-emption analysis and rely on the dormant Indian Commerce Clause, Art. I, § 8, cl. 3, to hold that on-reservation activities involving a resident tribe are presumptively beyond the reach of state law even in the absence of comprehensive federal regulation, thus placing the burden on the State to demonstrate that its intrusion is either condoned by Congress or justified by a compelling need to protect legitimate, specified state interests other than the generalized desire to collect revenue. He argues that adopting this approach is preferable for several reasons: it would provide guidance to the state courts addressing these issues, thus reducing the need for our case-by-case review of these decisions; it would avoid the tension created by focusing on the pervasiveness of federal regulation as a principal barrier to state assertions of authority when the primary federal goal is to encourage tribal self-determination and self-government; and it would place a higher burden on the State to articulate clearly its particularized interests in taxing the transaction and to demonstrate the services it provides in assisting the taxed transaction.
We do not believe it necessary to adopt this new approach — the existing pre-emption analysis governing these cases is sufficiently sensitive to many of the concerns expressed by the Solicitor General. Although clearer rules and presumptions promote the interest in simplifying litigation, our precedents announcing the scope of pre-emption analysis in this area provide sufficient guidance to state courts and also allow for more flexible consideration of the federal, state, and tribal interests at issue. We have consistently admonished that federal statutes and regulations relating to tribes and tribal activities must be “construed generously in order to comport with . . . traditional notions of [Indian] sovereignty and with the federal policy of encouraging tribal independence.” White Mountain, supra, at 144; see also McClanahan v. Arizona State Tax Comm’n, 411 U. S., at 174-175, and n. 13; Warren Trading Post Co. v. Arizona Tax Comm’n, 380 U. S., at 690-691. This guiding principle helps relieve the tension between emphasizing the pervasiveness of federal regulation and the federal policy of encouraging Indian self-determination. Although we must admit our disappointment that the courts below apparently gave short shrift to this principle and to our precedents in this area, we cannot and do not presume that state courts will not follow both the letter and the spirit of our decisions in the future.
HH HH HH
In sum, the comprehensive federal regulatory scheme and the express federal policy of encouraging tribal self-sufficiency in the area of education preclude the imposition of the state gross receipts tax in this case. Accordingly, the judgment of the New Mexico Court of Appeals is reversed, and the case is remanded for further proceedings not inconsistent with this opinion.
It is so ordered.
On July 8, 1970, in his Message to the Congress on Indian Affairs, President Nixon referred specifically to these efforts of the Board to assume responsibility for the education of tribal children abandoned by the State as a “notable exampl[e]” of Indian self-determination. 6 Weekly-Comp. of Pres. Doc. 894, 899 (1970).
See Pub. L. 93-245, 87 Stat. 1073 (1973) (amending Pub. L. 93-120, 87 Stat. 431 (1973) to specifically earmark funds appropriated there for the construction of the Ramah school facility); Pub. L. 93-404, 88 Stat. 810 (1974); Pub. L. 94-165, 89 Stat. 985 (1975); Pub. L. 95-74, 91 Stat. 293 (1977).
Article VI of the 1868 Treaty between the United States and the Navajo Tribe, 15 Stat. 669, provides that “[i]n order to insure the civilization of the Indians entering into this treaty, the necessity of education is admitted.”
Although these regulations did not become effective until several months after the BIA and the Board had executed the initial contracts, the Secretary and the BIA had applied similar requirements under the authority of the Johnson-O’Malley Act, 48 Stat. 596, 25 U. S. C. § 452 et seq. In any event, the two subsequent agreements between the BIA, the Board and Lembke, accounting for two-thirds of the total construction, were signed after the effective date of these regulations, which clearly authorize the BIA to monitor these construction agreements.
Justice Rehnquist asserts that the comprehensive federal regulatory scheme outlined above “do[es] not regulate school construction, which is the activity taxed.” Post, at 851. The dissent fails to explain, however, how this fact distinguishes this case from White Mountain. In that case, we struck down Arizona’s use fuel tax and motor carrier license tax, not because of any federal interest in gasoline, licenses, or highways, but because the imposition of these state taxes on a non-Indian contractor doing work on the reservation was pre-empted by the “comprehensive regulation of the harvesting and sale of tribal timber.” 448 U. S., at 151. We find that New Mexico is similarly precluded from impeding the federal interest in the construction of autonomous Indian educational institutions by imposing its gross receipts tax on Lembke. Justice Rehnquist’s contention that the New Mexico tax is somehow compatible with this federal interest because such taxes “are as much a normal cost of school construction as the cost of cement and labor,” post, at 855, is also foreclosed by White Mountain. Surely, state use fuel and motor carrier license taxes are considered part of the cost of harvesting and marketing timber. Yet in White Mountain, we concluded that these taxes impeded the federal interest in “guaranteeing Indians that they will ‘receive . . . the benefit of whatever profit [the forest] is capable of yielding,’” 448 U. S., at 149, despite the dissent’s argument that the taxes amounted to less than 1% of the annual profits produced by the logging operation. Here, as in White Mountain, Justice Rehnquist continues to press this argument.
Appellee would have us impute congressional awareness and approval of the state gross receipts tax from appropriations bills which earmarked funds for the construction of these facilities, see n. 2, supra. Brief for Appellee 21-22. Appellee strains to find this awareness and approval by arguing that the same architects who prepared the cost estimates and requests that the Board submitted to Congress also prepared the bid specifications pursuant to which Lembke submitted its bid. However, as we have indicated, the bid specifications only required prospective bidders to include “all taxes required by law,” and the submitted bids did not specify the gross receipts tax as a separate line item. Supra, at 835. Therefore, it is by no means clear, and the Board disputes the contention, that the Board ever intended to have these state taxes included in the construction costs of its school facilities. Furthermore, there is absolutely no indication that Congress was even made aware of the existence of these taxes when it appropriated funds for the construction of the Ramah Navajo school. In any event, as we have noted in a related context, courts should be wary of inferring congressional intent to alter the force of existing law from an appropriations Act. Cf. TVA v. Hill, 437 U. S. 153, 189-191 (1978).
Of course, these statutes and regulations do not prevent the States from providing for the education of Indian children within their boundaries. Indeed, the Self-Determination Act specifically authorizes the Secretary to enter into contracts with any State willing to construct educational institutions for Indian children on or near the reservation. 88 Stat. 2214, 25 U. S. C. § 458. This case would be different if the State were actively seeking tax revenues for the purpose of constructing, or assisting in the effort to provide, adequate educational facilities for Ramah Navajo children.
The Bureau of Revenue invites us to adopt the “legal incidence” test, under which the legal incidence and not the actual burden of the tax would control the pre-emption inquiry. Of course, in some contexts, the fact that the legal incidence of the tax falls on a non-Indian is significant. See Washington v. Confederated Tribes of Colville Indian Reservation, 447 U. S. 134, 150-151 (1980); Moe v. Salish & Kootenai Tribes, 425 U. S. 463 (1976). However, in White Mountain, 448 U. S., at 151, we found it significant that the economic burden of the asserted taxes would ultimately fall on the Tribe, even though the legal incidence of the tax was on the non-Indian logging company. Given the comprehensive federal regulatory scheme at issue here, we decline to allow the State to impose additional burdens on the significant federal interest in fostering Indian-run educational institutions, even if those burdens are imposed indirectly through a tax on a non-Indian contractor for work done on the reservation.
In Central Machinery Co. v. Arizona State Tax Comm’n, 448 U. S. 160 (1980), we held that the Indian trader statutes, 19 Stat. 200, 25 U. S. C. §261 et seq., pre-empted the State's jurisdiction to tax the sale of farm machinery to the Indian Tribe, notwithstanding the substantial services that the State undoubtedly provided to the off-reservation activities of the non-Indian seller. Presumably, the state tax revenues derived from Lembke’s off-reservation business activities are adequate to reimburse the State for the services it provides to Lembke.
We are similarly unpersuaded by the State’s argument that the significant services it provides to the Ramah Navajo Indians justify the imposition of this tax. The State does not suggest that these benefits are in any way related to the construction of schools on Indian land. Furthermore, the evidence introduced below by the State on this issue is far from clear. Although the State does provide services to the Ramah Navajo Indians, it receives federal funds for providing some of these services, and the State conceded at trial that it saves approximately $380,000 by not having to provide education for the Ramah Navajo children. App. 95, 105-106, 108.