opinion: Justice Marshall
  delivered the opinion of the Court.
  Montana, like many other States, imposes a severance tax on mineral production in the State. In this appeal, we consider whether the tax Montana levies on each ton of coal mined in the State, Mont. Code Ann. § 15-35-101 et seq. (1979), violates the Commerce and Supremacy Clauses of the United States Constitution.
  I
  Buried beneath Montana are large deposits of low-sulfur coal, most of it on federal land. Since 1921, Montana has imposed a severance tax on the output of Montana coal mines, including coal mined on federal land. After commissioning a study of coal production taxes in 1974, see House Resolutions Nos. 45 and 93, Senate Resolution No. 83, 1974 Mont. Laws 1619-1620, 1653-1654, 1683-1684 (Mar. 14 and 16, 1974); Montana Legislative Council, Fossil Fuel Taxation (1974), in 1975, the Montana Legislature enacted the tax schedule at issue in this case. Mont. Code Ann. § 15-35-103 (1979). The tax is levied at varying rates depending on the value, energy content, and method of extraction of the coal, and may equal, at a maximum, 30% of the “contract sales price.” Under the terms of a 1976 amendment to the Montana Constitution, after December 31, 1979, at least 50% of the revenues generated by the tax must be paid into a permanent trust fund, the principal of which may be appropriated only by a vote of three-fourths of the members of each house of the legislature. Mont. Const., Art. IX, § 5.
  Appellants, 4 Montana coal producers and 11 of their out-of-state utility company customers, filed these suits in Montana state court in 1978. They sought refunds of over $5.4 million in severance taxes paid under protest, a declaration that the tax is invalid under the Supremacy and Commerce Clauses, and an injunction against further collection of the tax. Without receiving any evidence, the court upheld the tax and dismissed the complaints.
  On appeal, the Montana Supreme Court affirmed the judgment of the trial court. -Mont.-, 615 P. 2d 847 (1980). The Supreme Court held that the tax is not subject to scrutiny under the Commerce Clause because it is imposed on the severance of coal, which the court characterized as an intrastate activity preceding entry of the coal into interstate commerce. In this regard, the Montana court relied on this Court’s decisions in Heisler v. Thomas Colliery Co., 260 U. S. 245 (1922), Oliver Iron Mining Co. v. Lord, 262 U. S. 172 (1923), and Hope Natural Gas Co. v. Hall, 274 U. S. 284 (1927), which employed similar reasoning in upholding state severance taxes against Commerce Clause challenges. As an alternative basis for its resolution of the Commerce Clause issue, the Montana court held, as a matter of law, that the tax survives scrutiny under the four-part test articulated by this Court in Complete Auto Transit, Inc. v. Brady, 430 U. S. 274 (1977). The Montana court also rejected appellants’ Supremacy Clause challenge, concluding that appellants had failed to show that the Montana tax conflicts with any federal statute.
  We noted probable jurisdiction, 449 TJ. S. 1033 (1980), to consider the important issues raised. We now affirm.
  II
  A
  As an initial matter, appellants assert that the Montana Supreme Court erred in concluding that the Montana tax is not subject to the strictures of the Commerce Clause. In appellants’ view, Heisler’s “mechanical” approach, which looks to whether a state tax is levied on goods prior to their entry into interstate commerce, no longer accurately reflects the law. Appellants contend that the correct analysis focuses on whether the challenged tax substantially affects interstate commerce, in which case it must be scrutinized under the Complete Auto Transit test.
  We agree that Heisler’s reasoning has been undermined by more recent cases. The Heisler analysis evolved at a time when the Commerce Clause was thought to prohibit the States from imposing any direct taxes on interstate commerce. See, e. g., Helson & Randolph v. Kentucky, 279 U. S. 245, 250-252 (1929); Ozark Pipe Line Corp. v. Monier, 266 U. S. 555, 562 (1925). Consequently, the distinction between intrastate activities and interstate commerce was crucial to protecting the States’ taxing power.
  The Court has, however, long since rejected any suggestion that a state tax or regulation affecting interstate commerce is immune from Commerce Clause scrutiny because it attaches only to a “local” or intrastate activity. See Hunt v. Washington Apple Advertising Comm’n, 432 U. S. 333, 350 (1977); Pike v. Bruce Church, Inc., 397 U. S. 137, 141-142 (1970); Nippert v. Richmond, 327 U. S. 416, 423-424 (1946). Correspondingly, the Court has rejected the notion that state taxes levied on interstate commerce are per se invalid. See, e. g., Washington Revenue Dept. v. Association of Wash. Stevedoring Cos., 435 U. S. 734 (1978); Complete Auto Transit, Inc. v. Brady, supra. In reviewing Commerce Clause challenges to state taxes, our goal has instead been to “establish a consistent and rational method of inquiry” focusing on “the practical effect of a challenged tax.” Mobil Oil Corp. v. Commissioner of Taxes, 445 U. S. 425, 443 (1980). See Moorman Mfg. Co. v. Bair, 437 U. S. 267, 276-281 (1978); Washington Revenue Dept. v. Association of Wash. Stevedor ing Cos., supra, at 743-751; Complete Auto Transit, Inc. v. Brady, supra, at 277-279. We conclude that the same “practical” analysis should apply in reviewing Commerce Clause challenges to state severance taxes.
  In the first place, there is no real distinction — in terms of economic effects — between severance taxes and other types of state taxes that have been subjected to Commerce Clause scrutiny. See, e. g., Michigan-Wisconsin Pipe Line Co. v. Calvert, 347 U. S. 157 (1954); Joseph v. Carter & Weekes Stevedoring Co., 330 U. S. 422 (1947), Puget Sound Stevedoring Co. v. State Tax Comm’n, 302 U. S. 90 (1937), both overruled in Washington Revenue Dept. v. Association of Wash. Stevedoring Cos., supra. State taxes levied on a “local” activity preceding entry of the goods into interstate commerce may substantially affect interstate commerce, and this effect is the proper focus of Commerce Clause inquiry. See Mobil Oil Corp. v. Commissioner of Taxes, supra, at 443. Second, this Court has acknowledged that “a State has a significant interest in exacting from interstate commerce its fair share of the cost of state government,” Washington Revenue Dept. v. Association of Wash. Stevedoring Cos., supra, at 748. As the Court has stated, “ ‘[e]ven interstate business must pay its way.’ ” Western Live Stock v. Bureau of Revenue, 303 U. S. 250, 254 (1938), quoting Postal Telegraph-Cable Co. v. Richmond, 249 U. S. 252, 259 (1919). Consequently, the Heisler Court’s concern that a loss of state taxing authority would be an inevitable result of subjecting taxes on “local” activities to Commerce Clause scrutiny is no longer tenable.
  We therefore hold that a state severance tax is not immunized from Commerce Clause scrutiny by a claim that the tax is imposed on goods prior to their entry into the stream of interstate commerce. Any contrary statements in Heisler and its progeny are disapproved. We agree with appellants that the Montana tax must be evaluated under Complete Auto Transit’s four-part test. Under that test, a state tax does not offend the Commerce Clause if it “is applied to an activity with a substantial nexus with the taxing State, is fairly apportioned, does not discriminate against interstate commerce, and is fairly related to services provided by the State.” 430 U. S., at 279.
  B
  Appellants do not dispute that the Montana tax satisfies the first two prongs of the Complete Auto Transit test. As the Montana Supreme Court noted, “there can be no argument here that a substantial, in fact, the only nexus of the severance of coal is established in Montana.” -Mont., at-, 615 P. 2d, at 855. Nor is there any question here regarding apportionment or potential multiple taxation, for as the state court observed, “the severance can occur in no other state” and “no other state can tax the severance.” Ibid. Appellants do contend, however, that the Montana tax is invalid under the third and fourth prongs of the Complete Auto Transit test.
  Appellants assert that the Montana tax “discriminate [s] against interstate commerce” because 90% of Montana coal is shipped to other States under contracts that shift the tax burden primarily to non-Montana utility companies and thus to citizens of other States. But the Montana tax is computed at the same rate regardless of the final destination of the coal, and there is no suggestion here that the tax is administered in a manner that departs from this evenhanded formula. We are not, therefore, confronted here with the type of differential tax treatment of interstate and intrastate commerce that the Court has found in other “discrimination” cases. See, e. g., Maryland v. Louisiana, 451 U. S. 725 (1981); Boston Stock Exchange v. State Tax Comm’n, 429 U. S. 318 (1977); cf. Lewis v. BT Investment Managers, Inc., 447 U. S. 27 (1980); Philadelphia v. New Jersey, 437 U. S. 617 (1978).
  Instead, the gravamen of appellants’ claim is that a state tax must be considered discriminatory for purposes of the Commerce Clause if the tax burden is borne primarily by out-of-state consumers. Appellants do not suggest that this assertion is based on any of this Court’s prior discriminatory tax cases. In fact, a similar claim was considered and rejected in Heisler. There, it was argued that Pennsylvania had a virtual monopoly of anthracite coal and that, because 80% of the coal was shipped out of State, the tax discriminated against and impermissibly burdened interstate commerce. 260 U. S., at 251-253. The Court, however, dismissed these factors as “adventitious considerations.” Id., at 259. We share the Heisler Court’s misgivings about judging the validity of a state tax by assessing the State’s “monopoly” position or its “exportation” of the tax burden out of State.
  The premise of our discrimination cases is that “[t]he very purpose of the Commerce Clause was to create an area of free trade among the several States.” McLeod v. J. E. Dilworth Co., 322 U. S. 327, 330 (1944). See Hunt v. Washington Apple Advertising Comm’n, 432 U. S., at 350; Boston Stock Exchange v. State Tax Comm’n, supra, at 328. Under such a regime, the borders between the States are essentially irrelevant. As the Court stated in West v. Kansas Natural Gas Co., 221 U. S. 229, 255 (1911), “‘in matters of foreign and interstate commerce there are no state lines.’ ” See Boston Stock Exchange v. State Tax Comm’n, supra, at 331-332. Consequently., to accept appellants’ theory and invalidate the Montana tax solely because most of Montana’s coal is shipped across the very state borders that ordinarily are to be considered irrelevant would require a significant and, in our view, unwarranted departure from the rationale of our prior discrimination cases.
  Furthermore, appellants’ assertion that Montana may not “exploit” its “monopoly” position by exporting tax burdens to other States, cannot rest on a claim that there is need to protect the out-of-state Consumers of Montana coal from discriminatory tax treatment. As previously noted, there is no real discrimination in this case; the tax burden is borne according to the amount of coal consumed and not according to any distinction between in-state and out-of-state consumers. Rather, appellants assume that the Commerce Clause gives residents of one State a right of access at “reasonable” prices to resources located in another State that is richly endowed with such resources, without regard to whether and on what terms residents of the resource-rich State have access to the resources. We are not convinced that the Commerce Clause, of its own force, gives the residents of one State the right to control in this fashion the terms of resource development and depletion .in a sister State. Cf. Philadelphia v. New Jersey, supra, at 626.
  In any event, appellants’ discrimination theory ultimately collapses into their claim that the Montana tax is invalid under the fourth prong of the Complete Auto Transit test: that the tax is not “fairly related to the services provided by the State.” 430 U. S., at 279. Because appellants concede that Montana may impose some severance tax on coal mined in the State, the only remaining foundation for their discrimination theory is a claim that the tax burden borne by the out-of-state consumers of Montana coal is excessive. This is, of course, merely a variant of appellants’ assertion that the Montana tax does not satisfy the “fairly related” prong of the Complete Auto Transit test, and it is to this contention that we now turn.
  Appellants argue that they are entitled to an opportunity to prove that the amount collected under the Montana tax is not fairly related to the additional costs the State incurs because of coal mining. Thus, appellants’ objection is to the rate of the Montana tax, and even then, their only complaint is that the amount the State receives in taxes far exceeds the value of the services provided to the coal mining industry. In objecting to the tax on this ground, appellants may be assuming that the Montana tax is, in fact, intended to reimburse the State for the cost of specific services furnished to the coal mining industry. Alternatively, appellants could be arguing that a State’s power to tax an activity connected to interstate commerce cannot exceed the value of the services specifically provided to the activity. Either way, the premise of appellants’ argument is invalid. Furthermore, appellants have completely misunderstood the nature of the inquiry under the fourth prong of the Complete Auto Transit test.
  The Montana Supreme Court held that the coal severance tax is “imposed for the general support of the government.” -Mont., at-, 615 P. 2d, at 856, and we have no reason to question this characterization of the Montana tax as a general revenue tax. Consequently, in reviewing appellants’ contentions, we put to one side those cases in which the Court reviewed challenges to “user” fees or “taxes” that were designed and defended as a specific charge imposed by the State for the use of state-owned or state-provided transportation or other facilities and services. See, e. g., Evans ville-Vanderburgh Airport Authority Dist. v. Delta Airlines, Inc., 405 U. S. 707 (1972); Clark v. Paul Cray, Inc., 306 U. S. 583 (1939); Ingels v. Morf, 300 U. S. 290 (1937).
  This Court has indicated that States have considerable latitude in imposing general revenue taxes. The Court has, for example, consistently rejected claims that the Due Process Clause of the Fourteenth Amendment stands as a barrier against taxes that are “unreasonable” or “unduly burdensome.” See, e. g., Pittsburgh v. Alco Parking Corp., 417 U. S. 369 (1974); Magnano Co. v. Hamilton, 292 U. S. 40 (1934); Alaska Fish Salting & By-Products Co. v. Smith, 255 U. S. 44 (1921). Moreover, there is no requirement under the Due Process Clause that the amount of general revenue taxes collected from a particular activity must be reasonably related to the value of the services provided to the activity. Instead, our consistent rule has been:
  “Nothing is more familiar in taxation than the imposition of a tax upon a class or upon individuals who enjoy no direct benefit from its expenditure, and who are not responsible for the condition to be remedied.
  “A tax is not an assessment of benefits. It is, as we have said, a means of distributing the burden of the cost of government. The only benefit to which the taxpayer is constitutionally entitled is that derived from his enjoyment of the privileges of living in an organized society, established and safeguarded by the devotion of taxes to public purposes. Any other view would preclude the levying of taxes except as they are used to compensate for the burden on those who pay them, and would involve abandonment of the most fundamental principle of government — that it exists primarily to provide for the common good.” Carmichael v. Southern Coal & Coke Co., 301 U. S. 495, 521-523 (1937) (citations and footnote omitted).
  See St. Louis & S. W. R. Co. v. Nattin, 277 U. S. 157, 159 (1928); Thomas v. Gay, 169 U. S. 264, 280 (1898).
  There is no reason to suppose that this latitude afforded the States under the Due Process Clause is somehow divested by the Commerce Clause merely because the taxed activity has some connection to interstate commerce; particularly when the tax is levied on an activity conducted within the State. “The exploitation by foreign corporations [or consumers] of intrastate opportunities under the protection and encouragement of local government offers a basis for taxation as unrestricted as that for domestic corporations.” Ford Motor Co. v. Beauchamp, 308 U. S. 331, 334-335 (1939); see also Ott v. Mississippi Valley Barge Line Co., 336 U. S. 169 (1949). To accept appellants’ apparent suggestion that the Commerce Clause prohibits the States from requiring an activity connected to interstate commerce to contribute to the general cost of providing governmental services, as distinct from those costs attributable to the taxed activity, would place such commerce in a privileged position. But as we recently reiterated, “‘[i]t was not the purpose of the commerce clause to relieve those engaged in interstate commerce from their just share of state tax burden even though it increases the cost of doing business.’ ” Colonial Pipeline Co. v. Traigle, 421 U. S. 100, 108 (1975), quoting Western Live Stock v. Bureau of Revenue, 303 U. S., at 254. The “just share of state tax burden” includes sharing in the cost of providing “police and fire protection, the benefit of a trained work force, and The advantages of a civilized society.’.” Exxon Corp. v. Wisconsin Dept. of Revenue, 447 U. S. 207, 228 (1980), quoting Japan Line, Ltd. v. County of Los Angeles, 441 U. S. 434, 445 (1979). See Washington Revenue Dept. v. Association of Wash. Stevedoring Cos., 435 U. S., at 750-751; id., at 764 (Powell, J., concurring in part and concurring in result); General Motors Corp. v. Washington, 377 U. S. 436, 440-441 (1964).
  Furthermore, there can be no question that Montana may constitutionally raise general revenue by imposing a 'severance tax on coal mined in the State. The entire value of the coal, before transportation, originates in the State, and mining of the coal depletes the resource base and wealth of the State, thereby diminishing a future source of taxes and economic activity. Cf. Maryland v. Louisiana, 451 U. S., at 758-759. In many respects, a severance tax is like a real property tax, which has never been doubted as a legitimate means of raising revenue by the situs State (quite apart from the right of that or any other State to tax income derived from use of the property). See, e. g., Old Dominion S.S. Co. v. Virginia, 198 U. S. 299 (1905); Western Union Telegraph Co. v. Missouri ex rel. Gottlieb, 190 U. S. 412 (1903); Postal Telegraph Cable Co. v. Adams, 155 U. S. 688 (1895). When, as here, a general revenue tax does not discriminate against interstate commerce and is apportioned to activities occurring within the State, the State “is free to pursue its own fiscal policies, unembarrassed by the Constitution, if by the practical operation of a tax the state has exerted its power in relation to opportunities which it has given, to protection which it has afforded, to benefits which it has conferred by the fact of being an orderly, civilized society.” Wisconsin v. J. C. Penney Co., 311 U. S. 435, 444 (1940). As we explained in General Motors Corp. v. Washington, supra, at 440-441:
  “[T]he validity of the tax rests upon whether the State is exacting a constitutionally fair demand for that aspect of interstate commerce to which it bears a special relation. For our purposes, the decisive issue turns on the operating incidence of the tax. In other words, the question is whether the State has exerted its power in proper proportion to appellant’s activities within the State and to appellant’s consequent enjoyment of the opportunities and protections which the State has afforded. ... As was said in Wisconsin v. J. C. Penney Co., 311 U. S. 435, 444 (1940), ‘[t]he simple but controlling question is whether the state has given anything for which it can ask return.’ ”
  The relevant inquiry under the fourth prong of the Complete Auto Transit test is not, as appellants suggest, the amount of the tax or the value of the benefits allegedly bestowed as measured by the costs the State incurs on account of the taxpayer’s activities. Rather, the test is closely connected to the first prong of the Complete Auto Transit test. Under this threshold test, the interstate business must have a substantial nexus with the State before any tax may be levied on it. See National Bellas Hess, Inc. v. Illinois Revenue Dept., 386 U. S. 753 (1967). Beyond that threshold requirement, the fourth prong of the Complete Auto Transit test imposes the additional limitation that the measure of the tax must be reasonably related to the extent of the contact, since it is the activities or presence of the taxpayer in the State that may properly be made to bear a “just share of state tax burden,” Western Live Stock v. Bureau of Revenue, 303 U. S., at 254. See National Geographic Society v. California Board of Equalization, 430 U. S. 551 (1977); Standard Pressed Steel Co. v. Washington Revenue Dept., 419 U. S. 560 (1975). As the Court explained in Wisconsin v. J. C. Penney Co., supra, at 446 (emphasis added), “the incidence of the tax as well as its measure [must be] tied to the earnings which the State . .. has made possible, insofar as government is the prerequisite for the fruits of civilization for which, as Mr. Justice Holmes was fond of saying, we pay taxes.”
  Against this background, we have little difficulty concluding that the Montana tax satisfies the fourth prong of the Complete Auto Transit test. The “operating incidence” of the tax, see General Motors Corp. v. Washington, 377 U. S., at 440-441, is on the mining of coal within Montana. Because it is measured as a percentage of the value of the coal taken, the Montana tax is in “proper proportion” to appellants’ activities within the State and, therefore, to their “consequent enjoyment of the opportunities and protections which the State has afforded” in connection with those activities. Id., at 441. Cf. Nippert v. Richmond, 327 U. S., at 427. When a tax is assessed in proportion to a taxpayer’s activities or presence in a State, the taxpayer is shouldering its fair share of supporting the State’s provision of “police and fire protection, the benefit of a trained work force, and 'the advantages of a civilized society.’ ” Exxon Corp. v. Wisconsin Dept. of Revenue, 447 U. S., at 228, quoting Japan Line, Ltd. v. County of Los Angeles, 441 U. S., at 445.
  Appellants argue, however, that the fourth prong of the Complete Auto Transit test must be construed as requiring a factual inquiry into the relationship between the revenues generated by a tax and costs incurred on account of the taxed activity, in order to provide a mechanism for judicial disapproval under the Commerce Clause of state taxes that are excessive. This assertion reveals that appellants labor under a misconception about a court’s role in cases such as this. The simple fact is that the appropriate level or rate of taxation is essentially a matter for legislative, and not judicial, resolution. See Helson & Randolph v. Kentucky, 279 U. S. 245, 252 (1929); cf. Pittsburgh v. Alco Parking Corp., 417 U. S. 369 (1974); Magnano Co. v. Hamilton, 292 U. S. 40 (1934). In essence, appellants ask this Court to prescribe a test for the validity of state taxes that would require state and federal courts, as a matter of federal constitutional law, to calculate acceptable rates or levels of taxation of activities that are conceded to be legitimate subjects of taxation. This we decline to do.
  In the first place, it is doubtful whether any legal test could adequately reflect the numerous and competing economic, geographic, demographic, social, and political considerations that must inform a decision about an acceptable rate or level of state taxation, and yet be reasonably capable of application in a wide variety of individual cases. But even apart from the difficulty of the judicial undertaking, the nature of the factfinding and judgment that would be required of the courts merely reinforces the conclusion that questions about the appropriate level of state taxes must be resolved through the political process. Under our federal system, the determination is to be made by state legislatures in the first instance and, if necessary, by Congress, when particular state taxes are thought to be contrary to federal interests. Cf. Mobil Oil Corp. v. Commissioner of Taxes, 445 U. S., at 448-449; Moorman Mfg. Co. v. Bair, 437 U. S., at 280.
  Furthermore, the reference in the cases to police and fire protection and other advantages of civilized society is not, as appellants suggest, a disingenuous incantation designed to avoid a more searching inquiry into the relationship between the value of the benefits conferred on the taxpayer and the amount of taxes it pays. Rather, when the measure of a tax is reasonably related to the taxpayer’s activities or presence in the State — from which it derives some benefit such as the substantial privilege of mining coal — the taxpayer will realize, in proper proportion to the taxes it pays, “[t]he only benefit to which the taxpayer is constitutionally entitled ...[:] that derived from his enjoyment of the privileges of living in an organized society, established and safeguarded by the devotion of taxes to public purposes.” Carmichael v. Southern Coal & Coke Co., 301 U. S., at 522. Correspondingly, when the measure of a tax bears no relationship to the taxpayers’ presence or activities in a State, a court may properly conclude under the fourth prong of the Complete Auto Transit test that the State is imposing an undue burden on interstate commerce. See Nippert v. Richmond, 327 U. S., at 427; cf. Michigan-Wisconsin Pipe Line Co. v. Calvert, 347 U. S. 157 (1954). We are satisfied that the Montana tax, assessed under a formula that relates the tax liability to the value of appellant coal producers’ activities within the State, comports with the requirements of the Complete Auto Transit test. We therefore turn to appellants’ contention that the tax is invalid under the Supremacy Clause.
  Ill
  A
  Appellants contend that the Montana tax, as applied to mining of federally owned coal, is invalid under the Supremacy Clause because it “substantially frustrates” the purposes of the Mineral Lands Leasing Act of 1920, ch. 85, 41 Stat. 437, 30 U. S. C. § 181 et seg. (1976 ed. and Supp. Ill) (1920 Act), as amended by the Federal Coal Leasing Amendments Act of 1975, Pub. L. 94-377, 90 Stat. 1083 (1975 Amendments) . Appellants argue that under the 1920 Act, the “economic rents” attributable to the mining of coal on federal land — i. e., the difference between the cost of production (including a reasonable profit) and the market price of the coal— are to be captured by the Federal Government in the form of royalty payments from federal lessees. The payments thus received are then to be divided between the States and the Federal Government according to a formula prescribed by the Act. In appellants’ view, the Montana tax seriously undercuts and disrupts the 1920 Act’s division of revenues between the Federal and State Governments by appropriating directly to Montana a major portion of the “economic rents.” Appellants contend the Montana tax will alter the statutory scheme by causing potential coal producers to reduce the amount they are willing to bid in royalties on federal leases.
  As an initial matter, we note that this argument rests on a factual premise — that the principal effect of the tax is to shift a major portion of the relatively fixed “economic rents” attributable to the extraction of federally owned coal from the Federal Treasury to the State of Montana — that appears to be inconsistent with the premise of appellants’ Commerce Clause claims. In pressing their Commerce Clause arguments, appellants assert that the Montana tax increases the cost of Montana coal, thereby increasing the total amount of “economic rents,” and that the burden of the tax is borne by out-of-state consumers, not the Federal Treasury. But even assuming that the Montana tax may reduce royalty payments to the Federal Government under leases executed in Montana, this fact alone hardly demonstrates that the tax is inconsistent with the 1920 Act. Indeed, appellants’ argu-ment is substantially undermined by the fact that in § 32 of the 1920 Act, 41 Stat. 450, 30 U. S. C. § 189, Congress expressly authorized the States to impose severance taxes on federal lessees without imposing any limits on the amount of such taxes. Section 32, as set forth in 30 U. S. C. § 189, provides in pertinent part:
  “Nothing in this chapter shall be construed or held to affect the rights of the States or other local authority to exercise any rights which they may have, including the right to levy and collect taxes upon improvements, output of mines, or other rights, property, or assets of any lessee of the United States.”
  This Court had occasion to construe § 32 soon after it was enacted. The Court explained:
  “Congress . . . meant by the proviso to say in effect that, although the act deals with the letting of public lands and the relations of the [federal] government to the lessees thereof, nothing in it shall be so construed as to affect the right of the states, in respect of such private persons and corporations, to levy and collect taxes as though the government were not concerned. . . .
  “We think the proviso plainly discloses the intention of Congress that persons and corporations contracting with the United States under the act, should not, for that reason, he exempt from any form of state taxation other wise lawful.” Mid-Northern Oil Co. v. Walker, 268 U. S. 45, 48-50 (1925) (emphasis added).
  It necessarily follows that if the Montana tax is “otherwise lawful,” the 1920 Act does not forbid it.
  Appellants contend that the Montana tax is not “otherwise lawful” because it conflicts with the very purpose of the 1920 Act. We do not agree. There is nothing in the language or legislative history of either the 1920 Act or the 1975 Amendments to support appellants’ assertion that Congress intended to maximize and capture all “economic rents” from the mining of federal coal, and then to distribute the proceeds in accordance with the statutory formula. The House Report on the 1975 Amendments, for example, speaks only in terms of a congressional intent to secure a “fair return to the public.” H. R. Rep. No. 94-681, pp. 17-18 (1975). Moreover, appellants’ argument proves too much. By definition, any state taxation of federal lessees reduces the “economic rents” accruing to the Federal Government, and appellants’ argument would preclude any such taxes despite the explicit grant of taxing authority to the States by § 32. Finally, appellants’ contention necessarily depends on inferences to be drawn from §§ 7 and 35 of the 1920 Act, 30 U. S. C. §§ 207 and 191, which, as amended, prescribe the statutory formula for the division of the payments received by the Federal Government. See Complaint ¶¶ 38-41, J. S. App. 57a-58a. Yet § 32 of the 1920 Act, as set forth in 30 U. S. C. § 189, states that “[n]othing in this chapter” — which includes §§ 7 and 35 — “shall be construed or held to affect the rights of the States ... to levy and collect taxes upon . . . output of mines ... of any lessee of the United States.” And if, as the Court has held, the States may “levy and collect taxes as though the [federal] government were not concerned,” Mid-Northern Oil Co. v. Walker, supra, at 49, the manner in which the Federal Government collects receipts from its lessees and then shares them with the States has no bearing on the validity of a state tax. We therefore reject appellants’ contention that the Montana tax must be invalidated as inconsistent with the Mineral Lands Leasing Act.
  B
  The final issue we must consider is appellants’ assertion that the Montana tax is unconstitutional because it substantially frustrates national energy policies, reflected in several federal statutes, encouraging the production and use of coal, particularly low-sulfur coal such as is found in Montana. Appellants insist that they are entitled to a hearing to explore the contours of these national policies and to adduce evidence supporting their claim that the Montana tax substantially frustrates and impairs the policies.
  We cannot quarrel with appellants’ recitation of federal statutes encouraging the use of coal. Appellants correctly note that § 2 (6) of the Energy Policy and Conservation Act of 1975, 89 Stat. 874, 42 U. S. C. § 6201 (6), declares that one of the Act’s purposes is “to reduce the demand for petroleum products and natural gas through programs designed to provide greater availability and use of this Nation’s abundant coal resources.” And §102 (b)(3) of the Powerplant and Industrial Fuel Use Act of 1978 (PIFUA), 92 Stat. 3291, 42 U. S. C. § 8301 (b)(3) (1976 ed., Supp. Ill), recites a similar objective “to encourage and foster the greater use of coal and other alternate fuels, in lieu of natural gas and petroleum, as a primary energy source.” We do not, however, accept appellants’ implicit suggestion that these general statements demonstrate a congressional intent to pre-empt all state legislation that may have an adverse impact on the use of coal. In Exxon Corp. v. Governor of Maryland, 437 U. S. 117 (1978), we rejected a pre-emption argument similar to the one appellants urge here. There, it was argued that the “basic national policy favoring free competition” reflected in the Sherman Act pre-empted a state law regulating retail distribution of gasoline. Id., at 133. The Court acknowledged the conflict between the state law and this national policy, but rejected the suggestion that the “broad implications” of the Sherman Act should be construed as a congressional decision to pre-empt the state law. Id., at 133-134. Cf. New Motor Vehicle Bd. of California v. Orrin W. Fox Co., 439 U. S. 96, 110-111 (1978). As we have frequently indicated, “[p]re-emption of state law by federal statute or regulation is not favored ‘in the absence of persuasive reasons — either that the nature of the regulated subject matter permits no other conclusion, or that the Congress has unmistakably so ordained.’ ” Chicago & North Western Transp. Co. v. Kalo Brick & Tile Co., 450 U. S. 311, 317 (1981), quoting Florida Lime & Avocado Growers, Inc. v. Paul, 373 U. S. 132, 142 (1963). See Alessi v. Raybestos-Manhattan, Inc., 451 U. S. 504, 522 (1981); Jones v. Rath Packing Co., 430 U. S. 519, 525-526 (1977); Perez v. Campbell, 402 U. S. 637, 649 (1971). In cases such as this, it is necessary to look beyond general expressions of “national policy” to specific federal statutes with which the state law is claimed to conflict. The only specific statutory provisions favoring the use of coal cited by appellants are those in PIFUA.
  PIFUA prohibits new electric power plants or new major fuel-burning installations from using natural gas or petroleum as a primary energy source, and prohibits existing facilities from using natural gas as a primary energy source after 1989. 42 U. S. C. §§8311 (1), 8312 (a) (1976 ed., Supp. III). Appellants contend that “the manifest purpose of this Act to favor the use of coal is clear.” Brief for Appellants 37. As the statute itself makes clear, however, Congress did not intend PIFUA to pre-empt state severance taxes on coal. Section 601 (a)(1) of PIFUA, 92 Stat. 3323, 42 U. S. C. §8401 (a)(1) (1976 ed., Supp. Ill), provides for federal financial assistance to areas of a State adversely affected by increased coal or uranium mining, based upon findings by the Governor of the State that the state or local government lacks the financial resources to meet increased demand for housing or public services and facilities in such areas. Section 601 (a)(2), 42 U. S. C. § 8401 (a)(2) (1976 ed., Supp. Ill), then provides that
  “increased revenues, including severance tax revenues, royalties, and similar fees to the State and local governments which are associated with the increase in coal or uranium development activities . . . shall be taken into account in determining if a State or local government lacks financial resources.”
  This section clearly contemplates the continued existence, not the pre-emption, of state severance taxes on coal and other minerals.
  Furthermore, the legislative history of § 601 (a)(2) reveals that Congress enacted this provision with Montana’s tax specifically in mind. The Senate version of the PIFUA bill provided for impact aid, but the House bill did not. See H. R. Conf. Rep. No. 96-1749, p. 93 (1978). The Senate’s proposal for impact aid was opposed by the House conferees, who took the position that the States would be able to satisfy the demand for additional facilities and services caused by increased coal production through imposition of severance taxes and, in Western States, through royalties received under the Mineral Lands Leasing Act. See Transcript of the Joint Conference on Energy 1822, 1824, 1832, 1834-1837, 1839 (1977) (Tr.), reprinted in 2 U. S. Dept, of Energy, Legislative History: Powerplant and Industrial Fuel Use Act, 777, 779, 787, 789-792, 794 (1978) (Legislative History). In explaining the objections of the House conferees, Representative Eckhardt pointed out:
  “[T]he western states may collect severance taxes on that coal.
  “As I pointed out [see Tr. 1822, Legislative History, at 777], Montana already collects $3 a ton on severance taxes on coal and still enjoys a 50 percent royalty return. As the price of coal goes up . . . these severance taxes in addition go up.
  “This is a percentage tax, not a flat tax in most instances.
  “If we are going to merely determine on the basis of impact on a particular community in a state how much money is going to go to that community, without taking into account how much that community is enriched, I think we are going to have people who are so angry at us in Congress . . . .” Tr. 1835, Legislative History, at 790.
  Section 601 (a) (2) was obviously included in PIFUA as a response to these concerns, for it provides that severance taxes and royalties are to be “taken into account” in determining eligibility for impact aid. The legislative history of § 601 (a)(2) thus confirms what seems evident from the face of the statute — that Montana’s severance tax is not preempted by PIFUA. Since PIFUA is the only federal statute that even comes close to providing a specific basis for appellants’ claims that the Montana statute “substantially frustrates” federal energy policies, this aspect of appellants’ Supremacy Clause argument must also fail.
  IV
  In sum, we conclude that appellants have failed to demonstrate either that the Montana tax suffers from any of the constitutional defects alleged in their complaints, or that a trial is necessary to resolve the issue of the constitutionality of the tax. Consequently, the judgment of the Supreme Court of Montana is affirmed.
  So ordered.
  Under Mont. Code Ann. § 15-35-103 (1979), the value of the coal is determined by the “contract sales price” which is defined as “the price of coal extracted and prepared for shipment f. o. b. mine, excluding the amount charged by the seller to pay taxes paid on production . . . .” § 15-35-102 (1). Taxes paid on production are defined in § 15-35-102 (6). Because production taxes are excluded from the computation of the value of the coal, the effective rate of the tax is lower than the statutory rate.
  “Congress shall have Power ... To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes . . . .” U. S. Const., Art. I, § 8, cl. 3.
  The “Constitution, and the Laws of the United States . . . shall be the supreme Law of the Land ....’’ U. S. Const., Art. VI, el. 2.
  The Heisler Court explained that any other approach would
  “nationalize all industries, it would nationalize and withdraw from state jurisdiction and deliver to federal commercial control the fruits of California and the South, the wheat of the West and its meats, the cotton of the South, the shoes of Massachusetts and the woolen industries of other States, at the very inception of their production or growth, that is, the fruits unpicked, the cotton and wheat ungathered, hides and flesh of cattle yet ‘on the hoof,’ wool yet unshorn, and coal yet unmined, because they are .in varying percentages destined for and surely to be exported to States other than those of their production.” 260 U. S., at 259-260.
  Of course, the “fruits of California” and the “wheat of the West” have long since been held to be within the reach of the Commerce Clause. Pike v. Bruce Church, Inc., 397 U. S. 137 (1970); Wickard v. Filburn, 317 U. S. 111 (1942).
  The Heisler approach has been criticized as unresponsive to economic reality. See Hellerstein, Constitutional Constraints on State and Local Taxation of Energy Resources, 31 Nat. Tax. J. 245, 249 (1978); Brown, The Open Economy: Justice Frankfurter and the Position of the Judiciary, 67 Yale L. J. 219, 232-233 (1957); Developments in the Law: Federal Limitations on State Taxation of Interstate Business, 75 Harv. L. Rev. 953, 970-971 (1962) (Developments).
  The Heisler approach has forced the Court to draw distinctions that can only be described as opaque. Compare, for example, East Ohio Gas Co. v. Tax Comm’n, 283 U. S. 465 (1931) (movement of gas into local supply lines at reduced pressure constitutes local business), with State Tax Comm’n v. Interstate Natural Gas Co., 284 U. S. 41 (1931) (movement of gas into local supply lines constitutes part of interstate business).
  This is not to suggest, however, that Heisler and its progeny were wrongly decided.
  Nor do we share appellants’ apparent view that the Commerce Clause injects principles of antitrust law into the relations between the States by reference to such imprecise standards as whether one State is “exploiting” its “monopoly” position with respect to a natural resource when the flow of commerce among them is not otherwise impeded. The threshold questions whether a State enjoys a “monopoly” position and whether the tax burden is shifted out of State, rather than 'borne by in-state producers and consumers, would require complex factual inquiries about such issues as elasticity of demand for the product and alternative sources of supply. Moreover, under this approach, the constitutionality of a state tax could well turn on whether the in-state producer is able, through sales contracts or otherwise, to shift the burden of the tax forward to its out-of-state customers. As the Supreme Court of Montana observed, “[i]t would be strange indeed if the legality of a tax could be made to depend on the vagaries of the terms of contracts.” — Mont. —, —, 615 P. 2d 847, 856 (1980). It has been suggested that the “formidable evidentiary difficulties in appraising the geographical distribution of industry, with a view toward determining a state’s monopolistic position, might make the Court’s inquiry futile.” Developments, supra n. 5, at 970. See Hellerstein, supra n. 5. at 248-249.
  Since this Court has held that interstate commerce must bear its fair share of the state tax burden, see Western Live Stock v. Bureau of Revenue, 303 U. S. 250, 254 (1938), appellants cannot argue that no severance tax may be imposed on coal primarily destined for interstate commerce.
  Appellants expect to show that the “legitimate local impact costs [of coal mining] — for schools, roads, police, fire and health protection, and environmental protection and the like — might amount to approximately 2 [cents] per ton, compared to present average revenues from the severance tax alone of over $2.00 per ton.” Brief for Appellants 12. Appellants contend that inasmuch as 50% of the revenues generated by the Montana tax is “cached away, in effect, for unrelated and unknown purposes,” it is clear that the tax is not fairly related to the services furnished by the State. Reply Brief for Appellants 8.
  At oral argument before the Montana Supreme Court, appellants’ counsel suggested that a tax of “perhaps twelve and a half to fifteen percent of the value of the coal” would be constitutional. — Mont., at —, 615 P. 2d, at 851.
  Contrary to appellants’ suggestion, the fact that 50% of the proceeds of the severance tax is paid into a trust fund does not undermine the Montana court’s conclusion that the tax is a general revenue tax. Nothing in the Constitution prohibits the people of Montana from choosing to allocate a portion of current tax revenues for use by future generations.
  As the Court has stated, “such imposition, although termed a tax, cannot be tested by standards which generally determine the validity of taxes.” Interstate Transit, Inc. v. Lindsey, 283 U. S. 183, 190 (1931). Because such charges are purportedly assessed to reimburse the State for costs incurred in providing specific quantifiable services, we have required a showing, based on factual evidence in the record, that “the fees charged do not appear to be manifestly disproportionate to the services rendered ...” Clark v. Paul Gray, Inc., 306 U. S., at 599. See id., at 598-600; Ingels v. Morf, 300 U. S., at 296-297.
  One commentator has suggested that these “user” charges “are not true revenue measures and . . . the considerations applicable to ordinary tax measures do not apply.” P. Hartman, State Taxation of Interstate Commerce 20, n. 72 (1953). Instead, “user” fees “partak[e] ... of the nature of a rent charged by the State, based upon its proprietary interest in its public property, [rather] than of a tax, as that term is thought of in a technical sense.” Id., at 122. See generally id., at 122-130.
  Most of the States raise revenue by levying a severance tax on mineral production. The first such tax was imposed by Michigan in 1846. See U. S. Dept, of Agrie., State Taxation of Mineral Deposits and Production (1977). By 1979, 33 States had adopted some type of severance tax. See TJ. S. Bureau of Census, State Government Tax Collections in 1979, Table 3, p. 6 (1980).
  The fourth prong of the Complete Auto Transit test is derived from General Motors, J. C. Penney, and similar cases. See 430 U. S., at 279, n. 8; see also National Geographic Society v. California Board of Equalization, 430 U. S. 551, 558 (1977).
  Indeed, the words “amount” and “value” were not even used in Complete Auto Transit. See 430 U. S., at 279. Similarly, our cases applying the Complete Auto Transit test have not mentioned either of these words. See Exxon Corp. v. Wisconsin Dept. of Revenue, 447 U. S. 207, 228 (1980); Mobil Oil Corp. v. Commissioner of Taxes, 445 U. S. 425, 443 (1980); Japan Line, Ltd. v. County of Los Angeles, 441 U. S. 434, 444-445 (1979); Washington Revenue Dept. v. Association of Wash. Stevedoring Cos., 435 U. S. 734, 750 (1978); National Geographic Society v. California Board of Equalization, supra, at 558.
  In any event, the linchpin of appellants’ contention is the incorrect assumption that the amount of state taxes that may be levied on an activity connected to interstate commerce .is limited by the costs incurred by the State on account of that activity. Only then does it make sense to advocate judicial examination of the relationship between taxes paid and benefits provided. But as we have previously noted, see supra, at 623-624, interstate commerce may be required to contribute to the cost of providing all governmental services, including those services from which it arguably receives no direct "benefit.” In such circumstances, absent an equal protection challenge (which appellants do not raise), and unless a court is to second-guess legislative decisions about the amount or disposition of tax revenues, it is difficult to see how the court is to go about comparing costs and benefits in order to decide whether the tax burden on an activity connected to interstate commerce is excessive.
  Of course, a taxing statute may be judicially disapproved if it is “so arbitrary as to compel the conclusion that it does not involve an exertion of the taxing power, but constitutes, in substance and effect, the direct exertion of a different and forbidden power, as, for example, the confiscation of property.” Magnano Co. v. Hamilton, 292 U. S. 40, 44 (1934).
  The controversy over the Montana tax has not escaped the attention of the Congress. Several bills were introduced during the 96th Congress to limit the rate of state severance taxes. See S. 2695, H. R. 6625, H. R. 6654 and H. R. 7163. Similar bills have been introduced in the 97th Congress. See S. 178, H. R. 1313.
  As original ly enacted in 1920, § 35 of the Mineral Lands Leasing Act, ch. 85, 41 Stat. 450, 30 U. S. C. § 191 (1970 ed.), provided that all receipts from the leasing of public lands under the Act were to be paid into the United States Treasury and then divided as follows: 37.5% to the State in which the leased lands are located; 52.5% to the reclamation fund created by the Reclamation Act of 1902, ch. 1093, § 1, 32 Stat. 388, 43 U. S. C. §391; and the remaining 10% to be deposited in the Treasury under “miscellaneous receipts.”
  Section 35 was amended by § 9 (a) of the 1975 Amendments to provide for a new statutory formula which is currently in effect. Under this formula, the State in which the mining occurs receives 50% of the revenues, the reclamation fund receives 40%, and the United States Treasury the remaining 10%. 30 U. S. C. § 191.
  Indeed, appellants alleged in their complaints that the contracts between appellant coal producers and appellant utility companies require the utility companies to reimburse the coal producers for their severance tax payments, and that the ultimate incidence of the tax primarily falls on the utilities’ out-óf-state customers. Complaint ¶¶ 17, 18, App. to Juris. Statement (J. S. App.) 53a-54a. Presumably, with regard to these contracts, the Federal Government’s receipts will be unaffected by the Montana tax.
  Thus, in Exxon, after rejecting the "national policy” pre-emption argument, the Court went on to consider more focused allegations concerning alleged conflicts between the state law and specific provisions of the Robinson-Patman Act. 437 U. S., at 129-133.
  Appellants’ assertion that the Montana tax is pre-empted by the Clean Air Act, 42 U. S. C. §7401 et seq. (1976 ed., Supp. Ill), merits little discussion. The Clean Air Act does not mandate the use of coal; it merely prescribes standards governing the emission of sulfur dioxide when coal is used. Any effect those standards might have on the use of high or low sulphur coal is incidental.
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