We granted certiorari in this case to review a decision of the Court of Appeals for the Ninth Circuit that held that Alaska's requirement that timber taken from state lands be processed within the State prior to export was "implicitly authorized" by Congress and therefore does not violate the Commerce Clause. 464 U. S. 890 (1983). We hold that it was not authorized and reverse the judgment of the Court of Appeals.

I

In September 1980, the Alaska Department of Natural Resources published a notice that it would sell approximately 49 million board-feet of timber in the area of Icy Cape, Alaska, on October 23, 1980. The notice of sale, the prospectus, and the proposed contract for the sale all provided, pursuant to 11 Alaska Admin. Code § 76.130 (1974), that “[p]rimary manufacture within the State of Alaska will be required as a special provision of the contract."1 App. 35a. Under the primary-manufacture requirement, the successful bidder must partially process the timber prior to shipping it outside of the State. The requirement is imposed by contract and

2

'The proposed contract, which the successful bidder on the timber sale would have been required to sign, provided:

"Section 68. Primary Manufacture. Timber cut under this contract shall not be transported for primary manufacture outside the State of Alaska without written approval of the State.

"Primary Manufacture is defined under 11 AAC 76.130 and the Governor's policy statement of May 1974."

211 Alaska Admin. Code § 76.130 (1974) (repealed 1982), which authorized the contractual provision in question, provided:

"PRIMARY MANUFACTURE

"(a) The director may require that primary manufacture of logs, cordwood, bolts or other similar products be accomplished within the State of Alaska. “(b) The term primary manufacture means manufacture which is first in order of time or development. When used in relation to sawmilling, it

means

"(1) the breakdown process wherein logs have been reduced in size by a headsaw or gang saw to the extent that the residual cants, slabs, or planks

does not limit the export of unprocessed timber not owned by the State. The stated purpose of the requirement is to "protect existing industries, provide for the establishment of new industries, derive revenue from all timber resources, and manage the State's forests on a sustained yield basis." Governor's Policy Statement, App. 28a. When it imposes the requirement, the State charges a significantly lower price for the timber than it otherwise would. Brief for Respondents 6-7.

The major method of complying with the primary-manufacture requirement is to convert the logs into cants, which are logs slabbed on at least one side. In order to satisfy the Alaska requirement, cants must be either sawed to a maximum thickness of 12 inches or squared on four sides along their entire length.3

Petitioner, South-Central Timber Development, Inc., is an Alaska corporation engaged in the business of purchasing standing timber, logging the timber, and shipping the logs into foreign commerce, almost exclusively to Japan. It

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can be processed by resaw equipment of the type customarily used in log processing plants; or

“(2) manufacture of a product for use without further processing, such as structural timbers (subject to a firm showing of an order or orders for this form of product).

“(c) Primary manufacture, when used in reference to pulp ventures, means the breakdown process to a point where the wood fibers have been separated. Chips made from timber processing wastes shall be considered to have received primary manufacture. With respect to veneer or plywood production, it means the production of green veneer. Poles and piling, whether treated or untreated, when manufactured to American National Institute Standards specifications are considered to have received primary manufacture."

The local-processing requirement is now authorized by Alaska Admin. Code §§ 71.230, 71.910 (1982).

'Current regulations require that the cants be no thicker than 8 inches unless slabs are taken from all four sides. 11 Alaska Admin. Code § 71.910 (1982).

'Apparently, there is virtually no interstate market in Alaska timber because of the high shipping costs associated with shipment between

does not operate a mill in Alaska and customarily sells unprocessed logs. When it learned that the primary-manufacture requirement was to be imposed on the Icy Cape sale, it brought an action in Federal District Court seeking an injunction, arguing that the requirement violated the negative implications of the Commerce Clause. The District Court

American ports. Consequently, over 90% of Alaska timber is exported to Japan. Brief for Petitioner 14, n. 14.

5

Although it would appear at first blush that it would be economically more efficient to have the primary processing take place within Alaska, that is apparently not the case. Material appearing in the record suggests that the slabs removed from the log in the process of making cants are often quite valuable, but apparently cannot be used and are burned. Record, Exh. 11, p. 63. It appears that because of the wasted wood, cants are actually worth less than the unprocessed logs. An affidavit of a vice president of South-Central states in part:

"5. It is also my observation that within Alaska there is absolutely no market for domestic resawing of 'cant' or 'square' manufactured to State of Alaska specifications. In other words, a cant or square manufactured in Alaska would be virtually unsaleable within local Alaska sawmill markets. The reasons are:

"A. Any sawmill would prefer round logs for its sawmill operations and the small volume of round logs required would be readily available locally. "B. Round logs are preferable because they can be stored in the water and moved in the water, whereas cants must be transported on land.

"C. Once a log is placed on the sawmill carriage and the costs of getting it there have been incurred, it produces more lumber for the costs involved than does a cant.

"D. Also the round log is much less subject to deterioration from weather and outside conditions.

"6. South-Central had experience with attempting to make a sale of cants inside the State of Alaska. We had some cants at Jakalof Bay which were manufactured to State specifications, but which were not loaded aboard ships during that season. We attempted to market those cants to a sawmill in Anchorage, but found that just costs of transporting the cants from Jakalof Bay to Anchorage exceeded the highest possible sales price of the cants. Accordingly no sale was made.

"7. Based on the above statements and my observations of the Alaska timber industry, it is my firm conclusion that a cant or a square manufactured to State of Alaska primary manufacture specifications is marketable

agreed and issued an injunction. South-Central Timber Development, Inc. v. LeResche, 511 F. Supp. 139 (Alaska 1981). The Court of Appeals for the Ninth Circuit reversed, finding it unnecessary to reach the question whether, standing alone, the requirement would violate the Commerce Clause, because it found implicit congressional authorization in the federal policy of imposing a primary-manufacture requirement on timber taken from federal land in Alaska. South-Central Timber Development, Inc. v. LeResche, 693 F.2d 890 (1982).

We must first decide whether the court was correct in concluding that Congress has authorized the challenged requirement. If Congress has not, we must respond to respondents' submission that we should affirm the judgment on two grounds not reached by the Court of Appeals: (1) whether in the absence of congressional approval Alaska's requirement is permissible because Alaska is acting as a market participant, rather than as a market regulator; and (2), if not, whether the local-processing requirement is forbidden by the Commerce Clause.

II

See

Although the Commerce Clause is by its text an affirmative grant of power to Congress to regulate interstate and foreign commerce, the Clause has long been recognized as a self-executing limitation on the power of the States to enact laws imposing substantial burdens on such commerce. Lewis v. BT Investment Managers, Inc., 447 U. S. 27, 35 (1980); Hughes v. Oklahoma, 441 U. S. 322, 326 (1979); H. P. Hood & Sons, Inc. v. Du Mond, 336 U. S. 525, 534-538 (1949); Cooley v. Board of Wardens, 12 How. 299 (1852). It is equally clear that Congress may "redefine the distribution of power over interstate commerce" by "permit[ting] the

only in foreign commerce and cannot be sold for use within Alaska. It is also my firm conclusion that no sawmill in Alaska will manufacture a cant or square for any domestic Alaska market." App. 121a-122a.

states to regulate the commerce in a manner which would otherwise not be permissible." Southern Pacific Co. v. Arizona, 325 U. S. 761, 769 (1945). See also Sporhase v. Nebraska ex rel. Douglas, 458 U. S. 941, 958-960 (1982); New England Power Co. v. New Hampshire, 455 U. S. 331 (1982); Western & Southern Life Insurance Co. v. State Board of Equalization, 451 U. S. 648, 652-655 (1981); Prudential Insurance Co. v. Benjamin, 328 U. S. 408 (1946). The Court of Appeals held that Congress had done just that by consistently endorsing primary-manufacture requirements on timber taken from federal land. 693 F. 2d, at 893. Although the court recognized that cases of this Court have spoken in terms of express approval by Congress, it stated:

"But such express authorization is not always necessary. There will be instances, like the case before us, where federal policy is so clearly delineated that a state may enact a parallel policy without explicit congressional approval, even if the purpose and effect of the state law is to favor local interests." Ibid.

We agree that federal policy with respect to federal land is "clearly delineated," but the Court of Appeals was incorrect in concluding either that there is a clearly delineated federal policy approving Alaska's local-processing requirement or that Alaska's policy with respect to its timber lands is authorized by the existence of a "parallel" federal policy with respect to federal lands.

Since 1928, the Secretary of Agriculture has restricted the export of unprocessed timber cut from National Forest lands in Alaska. The current regulation, upon which the State places heavy reliance, provides:

"Unprocessed timber from National Forest System lands in Alaska may not be exported from the United States or shipped to other States without prior approval of the Regional Forester. This requirement is neces