the Robinson-Patman Act, is merely an exception to that statute's broad prohibition against discriminatory pricing. It created no new federal right; quite the contrary, it defined a specific, limited defense, and even narrowed the good-faith defense that had previously existed.23 To be sure, the defense is an important one, and the interpretation of its contours has been informed by the underlying national policy favoring competition which it reflects." But it is illogical to infer that by excluding certain competitive behavior from the general ban against discriminatory pricing, Congress intended to preempt the States' power to prohibit any conduct within that exclusion. This Court is generally reluctant to infer preemption, see, e. g., De Canas v. Bica, 424 U. S. 351, 357-358, n. 5; Merrill Lynch, Pierce, Fenner & Smith v. Ware, 414 U. S. 117, 127, and it would be particularly inappropriate to do so in this case because the basic purposes of the state statute and the Robinson-Patman Act are similar. Both reflect a policy choice favoring the interest in equal treatment of all customers

23 Section 2 of the original Clayton Act, 38 Stat. 730, established an absolute defense for a seller's reductions in price made "in good faith to meet competition . . . ." The legislative history of the Robinson-Patman Act shows that § 2 (b) was intended to limit that broad defense. See Standard Oil Co. v. FTC, 340 U. S. 231, 247-249, n. 14.

24 In holding that §2 (b) created a substantive, rather than merely a procedural, defense, the Court explained:

"The heart of our national economic policy long has been faith in the value of competition. In the Sherman and Clayton Acts, as well as in the Robinson-Patman Act, 'Congress was dealing with competition, which it sought to protect, and monopoly, which it sought to prevent.' Staley Mfg. Co. v. Federal Trade Comm'n, 135 F. 2d 453, 455. We need not now reconcile, in its entirety, the economic theory which underlies the Robinson-Patman Act with that of the Sherman and Clayton Acts. It is enough to say that Congress did not seek by the Robinson-Patman Act either to abolish competition or so radically to curtail it that a seller would have no substantial right of self-defense against a price raid by a competitor." Standard Oil Co., supra, at 248-249 (footnote omitted).

over the interest in allowing sellers freedom to make selective competitive decisions.25

Appellants point out that the Robinson-Patman Act itself may be characterized as an exception to, or a qualification of, the more basic national policy favoring free competition,26 and argue that the Maryland statute "undermin [es]" the competitive balance that Congress struck between the Robinson-Patman and Sherman Acts.27 This is merely another way of stating that the Maryland statute will have an anticompetitive effect. In this sense, there is a conflict between the statute and the central policy of the Sherman Act our "charter of economic liberty." Northern Pacific R. Co. v. United States, 356 U. S. 1, 4. Nevertheless, this sort of conflict cannot itself constitute a sufficient reason for invalidating the Maryland statute. For if an adverse effect on competition were, in and of itself, enough to render a state statute invalid, the States' power to engage in economic regulation would be effectively destroyed.28 We are, therefore, satisfied that neither the broad implications of the Sherman Act nor the Robinson-Patman Act can fairly

25 Just as the political and economic stimulus for the Robinson-Patman Act was the perceived need to protect independent retail stores from "chain stores," see U. S. Department of Justice, Report on the RobinsonPatman Act 114-124 (1977), so too the Maryland statute was prompted by the perceived need to protect independent retail service station dealers from the vertically integrated oil companies. 279 Md., at 422, 370 A. 2d, at 1109.

26 Indeed, many have argued that the Robinson-Patman Act is fundamentally anticompetitive and undermines the purposes of the Sherman Act. See generally U. S. Department of Justice Report, supra.

27 Brief for Appellants in No. 77-10, p. 80.

28 Appellants argue that Maryland has actually regulated beyond its boundaries, pointing to the possibility that they may have to extend voluntary allowances into neighboring States in order to avoid liability under the Robinson-Patman Act. See nn. 21 and 22, supra. But this alleged extra-territorial effect arises from the Robinson-Patman Act, not the Maryland statute.

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437 U.S.

be construed as a congressional decision to pre-empt the power of the Maryland Legislature to enact this law.

The judgment is affirmed.

So ordered.

MR. JUSTICE POWELL took no part in the consideration or decision of these cases.

MR. JUSTICE BLACKMUN, concurring in part and dissenting in part.

Although I agree that the Maryland Motor Fuel Inspection Law' does not offend substantive due process or federal anti

1 The presently challenged portions of the law were enacted four years ago and amended once since then. 1974 Md. Laws, ch. 854; 1975 Md. Laws, ch. 608. The statute is now codified as Md. Code Ann., Art. 56, § 157E (Supp. 1977), and reads:

"(a) For the purpose of this law all gasoline and special fuels sold or offered or exposed for sale shall be subject to inspection and analysis as hereinafter provided.

...

“(b) After July 1, 1974, no producer or refiner of petroleum products shall open a major brand, secondary brand or unbranded retail service station in the State of Maryland, and operate it with company personnel, a subsidiary company, commissioned agent, or under a contract with any person, firm, or corporation, managing a service station on a fee arrangement with the producer or refiner. The station must be operated by a retail service station dealer.

"(c) After July 1, 1975, no producer or refiner of petroleum products shall operate a major brand, secondary brand, or unbranded retail service station in the State of Maryland, with company personnel, a subsidiary company, commissioned agent, or under a contract with any person, firm, or corporation managing a service station on a fee arrangement with the producer or refiner. The station must be operated by a retail service station dealer.

"(d) Every producer, refiner, or wholesaler of petroleum products supplying gasoline and special fuels to retail service station dealers shall extend all voluntary allowances uniformly to all retail service station dealers supplied.

"(e) Every producer, refiner, or wholesaler of petroleum products supplying gasoline and special fuels to retail service station dealers shall

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trust policy, I dissent from Part III of the Court's opinion because it fails to condemn impermissible discrimination against interstate commerce in retail gasoline marketing. The divestiture provisions, Md. Code Ann., Art. 56, §§ 157E (b) and (c) (Supp. 1977) (hereinafter referred to as §§ (b) and (c)), preclude out-of-state competitors from retailing gasoline within Maryland. The effect is to protect in-state retail service station dealers from the competition of the out-of-state businesses. This protectionist discrimination is not justified by any legitimate state interest that cannot be vindicated by more evenhanded regulation. Sections (b) and (c), therefore, violate the Commerce Clause.2

I

In Maryland the retail marketing of gasoline is interstate commerce, for all petroleum products come from outside the State. Retailers serve interstate travelers. To the extent that particular retailers succeed or fail in their businesses, the interstate wholesale market for petroleum products is affected. Cf. Dean Milk Co. v. Madison, 340 U. S. 349 (1951).3 The

apply all equipment rentals uniformly to all retail service station dealers. supplied.

"(f) Every producer, refiner or wholesaler of petroleum products shall apportion uniformly all gasoline and special fuels to all retail service station. dealers during periods of shortages on an equitable basis, and shall not discriminate among the dealers in their allotments."

2 U. S. Const., Art. I, § 8, cl. 3:
"The Congress shall have Power

"To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes."

The inherent effect of local regulation of retail sales on interstate commerce is well illustrated by Dean Milk. The city of Madison forbade the sale of pasteurized milk unless pasteurization occurred at a plant located within five miles of the center of the city. General Ordinances of the City of Madison §7.21 (1949). Even though only local sale was prohibited, the Court considered the ordinance to be a regulation of interstate commerce.

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437 U.S.

regulation of retail gasoline sales is therefore within the scope of the Commerce Clause. See ibid.; Minnesota v. Barber, 136 U. S. 313 (1890).*

A

The Commerce Clause forbids discrimination against interstate commerce, which repeatedly has been held to mean that States and localities may not discriminate against the transactions of out-of-state actors in interstate markets. E. g., Hunt v. Washington Apple Advertising Comm'n, 432 U. S. 333, 350-352 (1977); Halliburton Oil Well Co. v. Reily, 373 U. S. 64, 69–73 (1963); Dean Milk Co. v. Madison, 340 U. S., at 354; Best & Co. v. Maxwell, 311 U. S. 454, 455-456 (1940). The discrimination need not appear on the face of the state or local regulation. "The commerce clause forbids discrimination, whether forthright or ingenious. In each case it is our duty to determine whether the statute under attack, whatever its name may be, will in its practical operation work discrimination against interstate commerce." Ibid. (footnote omitted). The state or local authority need not intend to discriminate in order to offend the policy of maintaining a free-flowing national economy. As demonstrated in Hunt, a statute that on its face restricts both intrastate and interstate transactions may violate the Clause by having the "practical effect" of discriminating in its operation. 432 U. S., at 350-352.

If discrimination results from a statute, the burden falls upon the state or local government to demonstrate legitimate local benefits justifying the inequality and to show that less discriminatory alternatives cannot protect the local interests.

Cf. Best & Co. v. Maxwell, 311 U. S. 454 (1940) (holding that taxation of local retailing was within the reach of the Commerce Clause); United States v. Frankfort Distilleries, Inc., 324 U. S. 293 (1945) (holding that retailing was interstate commerce within the scope of the Sherman Act). See generally Note, Gasoline Marketing Divestiture Statutes: A Preliminary Constitutional and Economic Assessment, 28 Vand. L. Rev. 1277, 1303 (1975).