delivered the opinion of the Court.
The purposes of the “Bituminous Coal Conservation Act of 1935,” involved in these suits, as declared by the title, are to stabilize the bituminous coal-mining industry and promote its interstate commerce; to provide for cooperative marketing of bituminous coal; to levy a tax on such coal and provide for a drawback under certain conditions; to declare the production, distribution, and use of such coal to be affected with a national public interest; to. conserve-the national resources of such coal; to provide for the general welfare, and for other purposes. C. 824, 49 Stat. 991. The constitutional validity of the act is challenged in each of the suits.
Nos. 636 and 651 are cross-writs of certiorari in a stockholder’s suit, brought in the Supreme Court of the District of Columbia by Carter against the Carter Coal Company and some of its officers, Guy T. Helvering (Commissioner of Internal Revenue of the United *279States), and certain other officers of the United States, to enjoin the coal company and its officers named from' filing an acceptance of the code provided for in said act, from paying any tax imposed upon the coal company under the authority of the act, and from complying with its provisions or the provisions of the code. The bill sought to enjoin the Commissioner of Internal Revenue and the other federal officials named from proceeding under the act in particulars specified, the details of which it is unnecessary to state.
Nó. 649 is a suit brought in a federal district court in Kentucky by petitioners against respondent collector of internal revenue for the district of Kentucky, to enjoin him from collecting or- attempting to collect the taxes sought to be imposed upon them by the act, on the ground of its unconstitutionality.
No. 650 is a stockholder’s suit brought in the same court against the coal company and some of its officers, to secure a mandatory injunction against their refusal to accept and operate under the provisions of the Bituminous Coal Code prepared in pursuance of the act.
By the terms of the act, every producer of bituminous coal within the United States is brought within its provisions.
Section -1 is a detailed assertion of circumstances thought to justify the act. It declares that the mining and distribution of bituminous coal throughout the United States by the producer are affected with a national public interest; and that the service of such coal in relation to industrial activities, transportation facilities, health and comfort of the people, conservation by controlled production and economical mining and marketing, maintenance of just and rational relations between the public, owners, producers and employees, the right of the public to constant and adequate supplies of coal at reasonable prices, and the general welfare of the nation, *280require that the bituminous coal industry should be regulated as the act provides. '
Section 1, among other things, further declares that the production and distribution by producers of such coal bear upon and directly affect interstate commerce, and render regulation of production and distribution imperative for the protection of such commerce;. that certain features connected with the production, distribution, and marketing .have led to waste of the national coal resources, disorganization of interstate commerce in such coal, and burdening and obstructing interstate commerce therein; that practices prevailing in the production of such coal directly 'affect interstate commerce and require regulation for the protection of that commerce; and that the right of mine workers to organize and collectively bargain for wages, hours of labor, and conditions of employment should be guaranteed in order to prevent constant wage cutting and disparate labor costs detrimental to fair interstate competition, and in order to avoid obstructions to interstate commerce that recur in industrial disputes over labor relations- at the mines. These declarations constitute not enactments of law, but legislative averments by way of inducement to the enactment which follows.
. The substantive legislation begins with § 2, which establishes in the Department of the Interior a National Bituminous Coal Commission, to be appointed and constituted as the section then specifically provides. Upon this commission is conferred the power to hear evidence and find facts upon which its orders and actions may be predicated.
Section 3 provides':
“There is hereby imposed upon the sale or other disposal of all bituminous coal produced within the United States an excise tax of 15 per centum on the sale price at the mine, or in the case of captive coal the-fair market *281value of such coal at the mine, such tax, subject to the later provisions of this section, to be payable to the United States by the producers of such coal, and to be payable monthly for each calendar month, on or before the first business day of the second succeeding month, and under such regulations, and in such manner, as shall be prescribed by the Commissioner of Internal Revenue: Provided, That in the case of captive coal produced as aforesaid, the Commissioner of Internal Revenue shall fix a price therefor at the current market price for the comparable kind, quality, and size of coals in the locality where the same is produced: Provided further, That any such coal producer who has filed with the National Bituminous Coal Commission his acceptance of the code provided for in section 4 of this Act, and who acts in compliance with the provisions of such code, shall be entitled to a drawback in the form of a credit upon the amount of such tax payable hereunder, equivalent to 90 per centum of the amount of such tax, to be allowed and deducted therefrom at the time settlement therefor is required, in such manner as shall be prescribed by the Commissioner of Internal Revenue. Such right or benefit of drawback shall apply to all coal sold or disposed of from and after the day of the producer’s filing with the Commission his acceptance of said code in such form of agreement as the Commission may prescribe. No producer shall by reason of his acceptance of the code provided for in section 4 or of the drawback of taxes provided in section 3 of this Act be held to be precluded or estopped from contesting the constitutionality of any provision of said code, or its validity as applicable to such producer.”
Section 4 provides that the commission shall formulate the elaborate provisions contained therein into a working agreement to be known as the Bituminous Coal Code. These provisions require the organization of twenty-three *282coal districts, each with a district board the membership of which is to be determined in a manner pointed out by the act. Minimum prices for coal are to be established by each of these boards, which is authorized to make such classification of coals and price variation as to mines and consuming market areas as it may deem proper. “In order to sustain the stabilization of wages, working conditions, and maximum hours of labor, said prices shall be established so as to yield a return per net ton for each district in a minimum price area, as such districts are identified and such area is defined in the subjoined table designated ‘Minimum-price area table,’ equal as nearly as may be to the weighted average of the total costs, per net ton, determined as hereinafter provided, of the tonnage of such minimum price area. The computation of the total costs shall include the cost of labor, supplies, power, taxes, insurance, workmen’s compensation, royalties, depreciation, and depletion (as determined by the Bureau of Internal Revenue in the computation of the Federal income tax) and all other' direct expenses of production, coal operators’ association dues, district board assessments for Board' operating expenses only levied under the code, and reasonable costs of selling and the cost of administration.” The district board must determine and adjust the total cost of the ascertainable tonnage produced in the district so as to give effect to any changes in wage rates, hours of employment, or other factors substantially affecting costs, which may have been established since January 1st, 1934.
Without repeating the long and involved provisions with regard to the fixing of minimum prices, it is enough to say that the act confers the power to fix the minimum price of coal at each and every coal mine in the United States, with such price variations as the board may deem necessary and proper. There is also a provision authorizing the commission, when deemed necessary in the public *283interest, to establish maximum prices in order to protect the consumer against unreasonably high prices.
All sales and contracts for the sale of coal are subject to the code prices provided for and in effect when such sales and contracts are made. Various unfair methods of competition are defined and forbidden.
The labor provisions of the code, found in Part III of the same section, require that in order to effectuate the purposes of the act the district boards and code members shall accept specified conditions contained in the code, among which are the following:
Employees to be given the right to organize and bargain collectively, through representatives of their own choosing, free from interference, restraint, or coercion of employers or their agents in respect of their, concerted activities.
Such employees to have the right of peaceable assemblage for the discussion of the principles of collective bargaining and to select their own check-weighman to inspect the weighing or measuring of coal.
A labor board is created, consisting of three members, to be appointed by the President and assigned to the Department of Labor. Upon this board is conferred authority to adjudicate disputes arising under the provisions just stated, and to determine whether or not an organization of employees had been promoted, or is controlled or dominated by an employer in its organization, management, policy, or election of representatives. The board “may order a code member to meet the representatives of its employees for the purpose of collective bargaining.”
Subdivision (g) of Part III provides:
“Whenever the maximum daily and weekly hours of labor are agreed upon in any contract or contracts negotiated between the producers of more than two-thirds the annual national tonnage production for the *284preceding calendar year and the representatives of more than one-half of the mine workers employed, such maximum hours of labor shall be accepted by all the code. members. • The wage agreement or agreements negotiated by collective bargaining in any district or group of two or more districts, between representatives of' producers of more than two-thirds of the annual tonnage production of such district or each of such districts in a contracting group during the preceding calendar year, and representatives of the majority of the mine workers therein, shall be filed with the Labor Board and shall be accepted as the minimum wages for the various classifications of labor by the code members operating in such district or group of districts.”
. The bill of complaint in Nos. 636 and 651 was filed in the Supreme Court of the District of Columbia on August 31, 1935, the day after the Coal Conservation' Act came into effect. That court, among other things, found that the suit was brought in good faith; that if Carter Coal Company should join the code it would be compelled to cancel existing contracts and pay its pro-portioriate share of administering the code; that .the production of bituminous coal is a local activity carried on within state borders; that coal is the nation’s greatest and primary source of energy, vital to the public welfaré, of the utmost importance to the industrial and economic life of the nation and the health and . comfort of its inhabitants; and that its distribution in interstate, commerce should be regular, continuous, and free of interruptions, obstructions, burdens, and restraints.
Other findings are to the effect that such coal is generally sold f. o. b. mine, and the. predominant portion of it shipped putside the state in which it is produced; that the distribution and marketing is predominantly interstate in character, and that the intrastate distribution *285and sale are so connected that interstate regulation cannot be accomplished effectively unless transactions of intrastate distribution and sale be regulated.
The court further found the existence of a condition of unrestrained and destructive competition in the system of distribution and marketing such coal, and of destructive price-cutting, burdening and restraining interstate commerce and dislocating and diverting its normal flow.
The court concluded as a matter of law that the bringing of the suit was not premature; that the plaintiff was without legal remedy, and rightly invoked ’ relief, in equity; that the labor provisions of the act and code were unconstitutional for reasons stated, but the price-fixing provisions were valid and constitutional; that the labor provisions are separable; and, since the provisions with respect to price-fixing and unfair competition are valid, the taxing provisions of the act could stand. Therefore, except for granting a permanent injunction against collection of the “taxes” accrued during the suit (Ex parte Young, 209 U. S. 123, 147-148), the court denied the relief sought, and dismissed the bill.
Appeals were taken to the United States Court of Appeals for the District of Columbia by the parties; but pending hearing and submission in that court, petitions for writs of certiorari were presented asking us to review the decree of the Supreme Court of the District without awaiting such hearing and submission. Because of the importance of the question and the advantage of a speedy final determination thereof, the writs were granted.
The remaining two suits (Nos. 649 and 650), involving the same questions, were brought in the federal District Court for the Western District of Kentucky. That court held the act valid and constitutional in its entirety and entered a decree accordingly. 12 F. Supp. 570. Appeals were taken to the Circuit Court of Appeals for the Sixth *286Circuit; but, as in' the Carter case and for the same reasons, this court granted writs of certiorari in advance of hearing and submission.
The questions involved will be considered under the following heads:
1. The right of stockholders to maintain suits of this character.
2. Whether the suits were prematurely brought.
3. Whether the exaction of 15 per centum on the sale price of coal at the mine is a tax or a penalty.
4. The purposes of the act as set forth in § 1, and the, authority vested in Congress by the Constitution to effectuate them.
• 5. Whether the labor provisions of the act can be upheld as an exercise of the power to regulate interstate commerce.
6. Whether subdivision (g) of Part III of the Code, is an unlawful delegation of power.
7. The constitutionality of the price-fixing provisions, and the question of severability—that is to say, whether if either the group of labor provisions or the group of price-fixing provisions be found constitutionally invalid, the other can stand as separable.
First. In the Carter case (Nos. 636 and 651) the stockholder who brought the suit had formally demanded of the board of directors that the company should not join the code, should refuse to pay the tax fixed by the act, and should bring appropriate judicial proceedings to prevent an unconstitutional and improper diversion of the assets of the company and to have determined the liability of the company under the act. The board considered the demand, determined that, while it believed the act to be unconstitutional and economically unsound and that it would adversely affect the business of the company-.if accepted, nevertheless it should accept the code provided for by the act because the penalty in the form *287of a 15% tax on* its gross sales would be seriously injurious and might result in bankruptcy. This action of the board was approved by a majority of the shareholders at~a special meeting called for the purpose of considering it.
In the Tway Company cases, the company itself brought suit to enjoin the enforcement of the act (No. 649); and a stockholder brought suit to compel the company to accept the code and operate under its provisions (No. 650).
Without repeating-the long averments of the several bills, we are of opinion that the suits were properly brought and were maintainable in a court of equity. The right of stockholders to bring such suits under the circumstances disclosed is settled by the recent decision of this court in Ashwander v. Tennessee Valley Authority, 297 U. S. 288, and requires no further discussion.
Second. That the suits were not prematurely brought also is clear. Section 2 of the act is mandatory in its requirement that the commission be appointed by the President. The provisions of § 4 that the code be formulated and promulgated-are-equally mandatory. The so-called tax of 15% is definitely imposed, and its exaction certain to ensue.
In Pennsylvania v. West Virginia, 262 U. S. 553, 592-595, suits were brought by Pennsylvania and Ohio against West Virginia to enjoin the defendant state from enforcing: an act of her legislature uoon the ground that it would injuriously affect or cut off the supply of natural .gas produced in her territory and carried by pipe lines into the territory of the plaintiff states and there sold and used. These suits were brought a few days after the West Virginia act became effective. No order had yet been made under it by the Public Service Commission, nor had it been tested in actual practice. But it appeared that the act was certain to operate as the complainant *288states apprehended it would. This court held that .the suit was not premature. “One does not have to await the consummation of threatened injury to obtain preventive relief. If the injury is certainly impending that is enough.”
Pierce v. Society of Sisters, 268 U. S. 510, 535-536, involved the constitutional validity of the Oregon Compulsory Education Act, which required every parent or other person having control of a child between the ages of eight and sixteen years to send him to the public school of the district where he resides. Suit was brought to enjoin the operation of the act by corporations owning and conducting private schools, bn the ground that their business and property were threatened with destruction through the unconstitutional compulsion exercised by the act upon parents and guardians. The suits were held to be not premature, although the effective date of' the act had not yet arrived. We said—“The injury to appellees was present and very real, not a mere possibility in the remote future. .If no relief had been possible prior to the effective date of the Act, the injury would have become irreparable. Prevention of impending injury by unlawful action is a well recognized function of courts of equity.”
• See, also, Terrace v. Thompson, 263 U. S. 197, 215-216; Swift & Co. v. United States, 276 U. S. 311, 326; Euclid v. Ambler Realty Co., 272 U. S. 365, 386; City Bank Co. v. Schnader, 291 U. S. 24, 34.
Third. The so-called excise tax of 15 per centum on the sale price of coal at the miñe, or, in the case of captive coal the fair market value, with its drawback allowance of 13%%, is clearly not a tax but a penalty. The exaction applies to all bituminous coal produced, whether it be sold, transported or consumed in interstate commerce, or transactions in respect of it be confined wholly *289to the limits of the state. It also applies to “captive coal”—that is to say, coal produced for the sole use of the producer.
It is very clear that the “excise tax” is not imposed for revenue but exacted as a penalty to compel compliance with the regulatory provisions of the act. The whole purpose of the exaction is to coerce what is called an agreement—which, of course, it is not, for it lacks the essential element of consent. One who does a thing in order to' avoid a monetary penalty does not agree; he yields to compulsion precisely the same as though he did so to avoid a'term in jail.
The exaction here is a penalty and not a tax within the. test laid down by this court in numerous cases. Child Labor Tax Case, 259 U. S. 20, 37-39; United States v. La Franca, 282 U. S. 568, 572; United States v. Constantine, 296 U. S. 287, 293 et seq.; United States v. Butler, 297 U. S. 1, 70. While the lawmaker is entirely free to ignore the ordinary meanings of words and make definitions of his own, Karnuth v. United States, 279 U. S. 231, 242; Tyler v. United States, 281 U. S. 497, 502, that device may not be employed so as to change the nature of the acts or things to which the words are applied. But it is not necessary to pursue the matter further: That the “tax” is in fact a penalty is not seriously in dispute. The position of the Government, as we understand it, is that the validity of the exaction does not rest upon the taxing power but upon the power of Congress to regulate interstate commerce; and that if the act in respect of the labor and price-fixing provisions' be not upheld, the “tax” must fall with them. - With that position we agree and confine our consideration accordingly.
Fourth. Certain recitals contained in the act plainly suggest that its makers were of opinion that its constitutionality could be sustained under some general federal *290power, thought to exist, apart from the specific grants of the Constitution. The fallacy of that view will be apparent when we recall fundamental principles which, although hitherto often expressed in varying forms of words, will bear repetition whenever their accuracy seems to be challenged. The recitals to which we refer are contained in § 1 (which is simply a preamble to the act), and, among others, are to the effect that the distribution of bituminous coal is of national interest, affecting the health and comfort of the people and the general welfare of the nation; that this circumstance, together with the necessity of maintaining just and rational relations between the public, owners, producers, and employees, and the right of the public to constant and adequate supplies at reasonable prices, require regulation of the industry as the act provides. These affirmations—and the further ones that the production and distribution of such coal “directly affect interstate commerce,” because of which and of the waste of the national coal resources and other circumstances, the regulation is necessary for the protection of such commerce—do not constitute an exertion of the luill of Congress which is legislation, but a recital of considerations which in the opinion of that body existed and justified the expression of its will in the present act. Nevertheless, this preamble may not be disregarded. On the contrary it is important, because it makes clear, except for the pure assumption that the conditions described “directly” affect interstate commerce, that the powers which Congress undertook to exercise are not specific but of the most general character—namely, to protect the general public interest and the health and comfort of the people, to conserve privately-owned coal, maintain just relations between producers and employees and others, and promote the general welfare, by controlling nation-wide production and distribution of coal. These, it may be conceded, are objects of great worth; *291but are they ends, the attainment of which has been committed by the Constitution to the federal government? This is a vital question; for nothing is more certain than that beneficent aims, however great or well directed, can never serve in lieu of constitutional power.
The ruling and firmly established principle is that the powers which the general government may exercise are only those specifically enumerated in the Constitution,’ and such implied powers as are necessary and proper to carry into effect the enumerated powers. Whether the end sought to be attained by an act of Congress is legitimate is wholly a matter of constitutional power and not at all of legislative discretion. Legislative congressional discretion begins with the choice of means and ends with the adoption of methods and details to carry the delegated powers into effect. The distinction between these two things—power and discretion—is not only very plain but very important. Eor while the powers are rigidly limited to the enumerations of the. Constitution, the means which may be employed to carry the powers into effect are not restricted, save that they must be appropriate, plainly adapted to the end, and. not prohibited by, but consistent with, the letter and spirit of the Constitution. McCulloch v. Maryland, 4 Wheat. 316, 421. Thus, it may be said that to a constitutional end many ways are open; but to an end not within the terms of the Constitution, all ways are closed.
The proposition, often advanced and as often discredited, that the power of the federal government inherently extends to purposes affecting.the nation as a whole with which the states severally cannot deal or cannot adequately deal, and the related notion that Congress, entirely apart from those powers delegated by the .Constitution, may enact laws to promote the general welfare, have never been accepted but always definitely rejected by this court. Mr. Justice Story, as early as 1816, *292laid down the cardinal rule, which has ever since been followed—that the general government “can claim no powers which are not granted to it by; the Constitution, and the powers actually granted, must be such as are expressly given, or given by necessary implication.” Martin v. Hunter’s Lessee, 1 Wheat. 304, 326. In the Framers Convention, the proposal to confer a general power akin to that just discussed was included in Mr. Randolph’s resolutions, the sixth of which, among other things, declared that.the National Legislature ought to enjoy the legislative rights vested in Congress by the Confederation, and “moreover to legislate in all cases to which the separate,States are incompetent, or in which the harmony of the United States may be interrupted by the exercise of individual Legislation.” The convention, however, declined to confer upon Congress power in such general terms; instead of which it carefully limited the powers which it thought wise to entrust to Congress by specifying them, thereby denying all others not granted expressly or by necessary implication. It made no grant of authority to Congress to legislate substantively for the general welfare, United States v. Butler,, supra, p. 64; and no such authority exists, save as the general welfare may be promoted by the exercise of the powers which are granted. Compare Jacobson v. Massachusetts, 197 U. S. 11, 22.
There are many subjects in respect of which the several states have not legislated in harmony with one another, and in which their varying laws and the failure of some of them to act at all have resulted in injurious confusion and embarrassment. See Addyston Pipe & Steel Co. v. United States, 175 U. S. 211, 232-233. The state laws with respect to marriage and divorce present a case in point; and the great necessity of national legislation on that subject has been from time to time vigorously urged. Other pertinent examples are laws with respect to nego *293tiable instruments, desertion and non-support, certain •phases of state taxation, and others which we do not pause to mention. In many of these fields of legislation, the necessity of bringing the applicable rules of law into general harmonious relation has been so great that a Commission on Uniform State Laws, composed of commissioners from every state in the Union, has for many years been industriously and successfully working to that end by preparing and securing the passage by the several states of uniform laws. If there be an easier and constitutional way to these desirable results through congressional action, it thus far has escaped discovery.
Replying directly to the suggestion advanced by counsel in Kansas v. Colorado, 206 U. S. 46, 89-90, to the effect that necessary powers national in their scope must bé found vested in Congress, though not expressly granted or essentially implied, this court said:
“But the proposition that there are legislative powers affecting the Nation as a whole which belong to, although not expressed in the grant of powers, is in direct conflict with the doctrine that this is a government of enumerated powers. That this is such a government clearly appears from the Constitution, independently of the Amendments, for otherwise there would be an instrument granting certain specified things made operative to grant other and distinct things. This natural construction of the original body of the Constitution is made absolutely certain by the Tenth Amendment. This amendment, which was seemingly adopted' with prescience of just such contention as the present, disclosed the widespread fear that the National Government might, under the pressure of a supposed general welfare, attempt to exercise powers which had not been granted. With equal determination the framers intended that no such assumption should ever find justification in the organic act, and that if in the future further powers seemed necessary they should *294be granted by the people in the manner they had provided for amending that act.”
The general rule with regard to the respective powers of the national and the state governments under the Constitution, is not in doubt. The states were before the Constitution; and, consequently, their legislative powers antedated the Constitution. Those who framed and those who adopted that instrument meant to carve from the general mass of legislative powers, then possessed by the states, only such portions as it was thought wise to confer upon the federal government; and in order that there should- be no uncertainty in respect of what was taken and what was left, the national powers of legislation were not aggregated but enumerated—with the result that what was not embraced by the enumeration remained vested in the states without change or impairment. Thus, “when it was found necessary to establish a national government for national purposes,” this court said in Munn v. Illinois, 94 U. S. 113, 124, “a part of the powers of the States and of the people of the States was granted to the United States and the people of the United States. This grant operated as a further limitation upon the powers of the States, so that now the governments of the States possess all the powers of the Parliament of England, except such as have been delegated to the United States or reserved by the people.” While the states are not sovereign in the true sense of that term, but only quasi-sovereign, yet in respect of all powers reserved to them they are supreme—“as independent of the general government as that government within its sphere is independent of the States.” Collector v. Day, 11 Wall. 113, 124. And since every addition to the national legislative power to some extent detracts from or invades the power of the states, it is of vital moment that, in order to preserve the fixed balance intended by the Constitution, the powers of the general government *295be not so extended as to embrace any not within the express terms of the several grants or the implications necessarily to be drawn therefrom. It is no longer open to question that the general government, unlike, the states, Hammer v. Dagenhart, 247 U. S. 251, 275, possesses no inherent power in respect of the internal affairs of the states; and emphatically not with regard to legislation. The question in respect of the inherent power of that government as to the external affairs of the nation and in the field of international law is a wholly different matter which it is not necessary now to consider. See, however, Jones v. United States, 137 U. S. 202, 212; Nishimura Ekiu v. United States, 142 U. S. 651, 659; Fong Yue Ting v. United States, 149 U. S. 698, 705 et seq.; Burnet v. Brooks, 288 U. S. 378, 396.
The determination of the Framers Convention and the ratifying convéntions to preserve compléte and unimpaired state self-government in all matters not committed to the general government is one of the plainest facts which emerge from the history of their deliberations. And adherence to that determination is incumbent equally upon the federal government and the states. State powers can neither be appropriated on the one hand nor abdicated on the other. As this court said in Texas v. White, 7 Wall. 700, 725—“the preservation of the States, and the maintenance of their governments, are as much within the design and care of the Constitution as the preservation of the Union and the maintenance of the National Government. The Constitution, in all its provisions, looks to an indestructible Union, composed of indestructible States.” Every journey to a forbidden end begins with the first step;, and the danger of such a step by the. federal government in the direction of inking over the powers of the states is. that the end of the journey may find the states so despoiled of their powers, or—what may amount to the same thing—so *296relieved of the responsibilities which possession of the powers necessarily enjoins, as to reduce them to little more than geographical subdivisions of the national domain. It is safe to say that if, when the Constitution was under consideration, it had been thought that any such danger lurked behind its plain words, it would never have been ratified.
And the Constitution itself is in every real sense a law— the lawmakers being the people themselves, in whom under our system all political power and sovereignty primarily resides, and through whom such power and sovereignty primarily speaks. It is by that law, and not otherwise, that the legislative, executive, and judicial agencies which it created exercise such political authority as they have been permitted to possess. The Constitution speaks for itself in terms so plain that to misunderstand their import is not rationally possible. “We the people of the United States,” it says, “do ordain and establish this Constitution . . .” Ordain and establish! These are definite words of enactment, and without more would stamp what follows with the dignity and character of law. The framers of the Constitution, however, were not content to let the matter rest here, but provided explicitly—“This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; . , . shall be the supreme Law of the Land; . . .” The supremacy of the Constitution as law is thus declared without qualification. That supremacy is absolute; the supremacy of a statute enacted by Congress is not-absolute but conditioned upon its being made in pursuance of the Constitution. And a judicial tribunal, clothed by that instrument with complete judicial power, and, therefore, by. the very nature of the power, required to ascertain and apply the law to the facts in every case or proceeding properly brought for adjudication, must apply the supreme law and reject the inferior stat*297ute whenever the two conflict. In the discharge of that-duty, the opinion of the lawmakers that a statute passed by them is valid must be given great weight, Adkins v. Children’s Hospital, 261 U. S. 525, 544; but their opinion, or the court’s opinion, that the statute will prove greatly or generally beneficial is wholly irrelevant to the inquiry. Schechter v. United States, 295 U. S. 495, 549-550.
We have set forth, perhaps at unnecessary length, the foregoing principles, because it seemed necessary to do so in order to demonstrate that the general purposes which the act recites, and which, therefore, unless the recitals be disregarded, Congress undertook to achieve, are beyond the power of Congress except so far, and only so far, as they may be realized by an exercise of sortie specific power granted by the Constitution. Proceeding by a process of elimination, which it is not necessary to follow in detail, we shall find no grant of power which authorizes Congress to legislate in respect of these general purposes unless it be found in the commerce clause—and this we now consider.
Fifth. Since the validity of the act depends, upon whether it is a regulation of interstate commerce, the nature and extent of the power conferred upon Congress by the commerce clause becomes the determinative question , in this branch of the case. The commerce clause vests in Congress the power—“To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes.” The function to be exercised is that of regulation. The thing to be regulated is the commerce described. In exercising the authority conferred by this clause of the Constitution, Congress is powerless to regulate anything which is not commerce, as it is powerless to do anything about commerce which is not regulation. We first inquire, then—What is commerce? The term, as this court many times has said, is *298one of extensive import. No all-embracing definition has ever been formulated. The question is to be approached both affirmatively' and negatively—that is to say, from the points of view as to what it includes and what it excludes.
In Gibbons v. Ogden, 9 Wheat. 1, 189-190, Chief Justice Marshall said:
“Commerce, undoubtedly, is traffic, but it is something more: it is intercourse. It describes the commercial intercourse between nations, and parts of nations, in all its branches, and is regulated by prescribing rules for carrying on that intercourse. . . .”
As used in the Constitution, the word “commerce” is the equivalent of the phrase “intercourse for the purposes of trade,” and includes transportation, purchase, sale, and exchange of commodities between the citizens of the different states. And the power to regulate commerce embraces the instruments by which commerce is carried on. Welton v. Missouri, 91 U. S. 275, 280; Addyston Pipe & Steel Co. v. United States, 175 U. S. 211, 241; Hopkins v. United States, 171 U. S. 578, 597. In Adair v. United States, 208 U. S. 161, 177, the phrase “Commerce among the several States” was defined as comprehending “traf-. fic, intercourse, trade, navigation, communication, the transit of persons and the .transmission of messages by telegraph—indeed, every species of commercial intercourse among the several States.” In Veazie v. Moor, 14 How. 568, 573-574, this court, after saying that the phrase could never be applied to transactions wholly internal, significantly added: “Nor can it be properly concluded, that, because the products of domestic enterprise in. agriculture or manufactures, or in the arts, may ultimately become the subjects of foreign commerce, that the control of the means or the encouragements by which enterprise is fostered and protected, is legitimately within the import of the phrase foreign commerce, or fairly im *299plied in. any investiture of the power to regulate such commerce. A pretension as far reaching as this, would extend to contracts between citizen and citizen of the same State, would control the pursuits of the planter, the grazier, the manufacturer, the mechanic, the immense operations of the collieries and mines and furnaces of the country; for there is not one of these avocations, the results of which may not- become the subjects of foreign commerce, and be borne either by turnpikes, canals, or railroads, from point to point within the several States, towards an ultimate destination, like the one above mentioned. ...”
The distinction between manufacture and commerce was discussed in Kidd v. Pearson, 128 U. S. 1, 20, 21, 22; and it was said:
“No distinction is more popular to the common mind, or more clearly expressed in economic and political literature, than that between manufacture and commerce. Manufacture -is transformation—the fashioning of raw materials into a change of form for use. The functions of commerce are different.... If it be held that the term includes the regulation of all such manufactures as are intended to be the subject of commercial transactions in the future, it is impossible -to deny that it would also include all productive industries that contemplate the same thing. The result would be that Congress would be invested, to the exclusion of the States, with the power to regulate, not only manufactures, but also agriculture, horticulture, stock raising, domestic fisheries, minirig—in short, every branch of human industry. For is there one of them that does not contemplate, more or less clearly, an interstate or foreign market? Does not the wheat grower of the Northwest and the cotton planter of the South, plant, cultivate, and harvest his crop with an eye on the prices at Liverpool, New York, and Chicago? The. power being vested in Congress and *300denied to the States, it would follow as. an inevitable result that the duty would devolve on Congress to regulate all of these delicate, multiform and vital interests— interests which in their nature are and must be local in all the details of their successful management.”
And then, as though foreseeing the present controversy, the opinion proceeds:
“Any movement toward the establishment of rules of production in this vast, country, with its many different climates and opportunities, could only be at the sacrifice of the peculiar advantages of a large part of the localities in it, if not of every one of them. On the other hand, any movement toward the local, detailed and incongruous legislation required by such interpretation would be about the widest possible departure from the declared object of the clause, in question. Nor this alone. Even in the exercisé of the power contended for, Congress would be confined to the regulation, not of certain branches of industry, however numerous, but to those instances in each and every branch where the producer contemplated an interstate market. ... A situation more paralyzing to the state governments, and more provocative of conflicts between the general government and the States, and. less likely to have been what the framers of the Constitution intended, it would be difficult to imagine.”
Chief Justice Fuller, speaking for this court in United States v. E. C. Knight Co., 156 U. S. 1, 12, 13, said:
“Doubtless the power- to control the manufacture of a given thing involves in a certain sense the control of its disposition, but this is a secondary’ and not the primary sense; and although the exercise of that power may result in bringing the operation of commerce, into play, it does not control it, and affects it only incidentally and indirectly. Commerce succeeds- to manufacture, and is not a part of it.
*301“It is vital that the independence of the commercial power and of the police power, and the delimitation between them, however sometimes perplexing, should always be recognized and observed, for while the one furnishes the strongest bond of union, the other is essential to the preservation of the autonomy of the States as required by our dual form of government; and acknowledged evils, however grave and urgent they may appear to be, had better be borne, than the risk be run, in the effort to suppress them, of more serious consequences by resort to expedients of even doubtful constitutionality.
“. . . The regulation of commerce applies to the subjects of commerce and not to matters of internal police. Contracts to buy, sell, or exchange goods to be transported among the several States, the transportation and its instrumentalities, and articles bought, sold, or exchanged for the purposes of such transit among the States, or put in the way of transit, may be regulated, but this is because they form part of interstate trade or commerce. The fact that an article is manufactured for export , to another State does not 'of itself make it an article of interstate commerce, and the intent of the manufacturer does not determine the time when the article or product passes from the control of the State and belongs to commerce. . . .”
That commodities produced or manufactured within a state are intended to be sold or transported outside the state does not render their production or manufacture subject to federal regulation under the commerce clause. As this court said in Coe v. Errol, 116 U. S. 517, 526, “Though intended for exportation, they may never be exported; the owner has a perfect right to change his mind; and until actually put in motion, for some place out of the State, or committed' to the custody of a carrier for transportation to such place, why may they not be regarded as .still remaining a part of the. general mass of *302property in the State?” It is true that this was said in respect of á challenged power of the state to impose a tax; but the query is equally pertinent where the question, as here, is with regard to the power of regulation. The case was relied upon in Kidd v. Pearson, supra, p. 26. “The application of the principles above announced,” it was there said, “to the case under consideration leads to a conclusion against the contention of the plaintiff in error. The police power of a State is as broad and plenary as its taxing power; and property within the State is subject to the operations of the former so long as it is within the regulating restrictions of the latter.”
In Heisler v. Thomas Colliery Co., 260 U. S. 245, 259-260, we held that the possibility, or even certainty of exportation of a product or article from a state did not determine it to be in interstate commerce before the commencement of its movement from the state. To hold otherwise “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.”
In Oliver Iron Co. v. Lord, 262 U. S. 172, 178, we said on the authority of numerous cited cases: “Mining is not interstate commerce, but, like manufacturing, is a local business subject to local regulation and taxation. .., Its character in this regard is intrinsic, is not affected by the intended use or disposal of the product, is not controlled by contractual engagements, and persists even *303though the business be conducted in close connection with interstate commerce.”
The same rule applies to the production of oil. “Such production is essentially a mining operation and therefore is not a part of interstate commerce even though the product obtained is intended to be and in fact is immediately shipped in such commerce.” Champlin Rfg. Co. v. Corporation Commission, 286 U. S. 210, 235. One who produces or manufactures a commodity, subsequently sold and shipped by him in interstate commerce, whether such sale and shipment were originally intended or not, has engaged in two distinct and separate activities. So far as he produces or manufactures a commodity, his business is purely local. So far as he sells and ships, or contracts to sell and ship, the commodity to customers in another state, he engages in interstate commerce. In respect of the former, hé is subject only to regulation by the state; in respect of the latter, to regulation only by the federal government. Utah Power & L. Co. v. Pfost, 286 U. S. 165, 182. Production is not commerce; but a step in preparation for commerce. Chassaniol v. Greenwood, 291 U. S. 584, 587.
We have seen that the word “commerce” is the equivalent of the phrase “intercourse for the purposes of trade.” Plainly, the incidents leading up to and culminating in the mining of coal do not constitute such intercourse. The employment of men, the fixing of their wages, hours of labor and working conditions, the bargaining in respect of these things—whether carried on separately or collectively—each and all constitute intercourse for the purposes of prodúction, not of trade. The latter is a thing apart from the relation of employer and employee, which in all producing occupations is purely local in character. Extraction of coal from the mine is the aim and the completed result of local activities. Commerce in the coal mined is not brought into being by *304force of these activities, but by negotiations, agreements, and circumstances entirely apart from production. Mining brings the subject matter of commerce into existence. Commerce disposes of it.
A consideration of the foregoing, and of many cases which might be added to those already cited, renders inescapable the conclusion that the effect of the labor provisions of the act, including those in respect of minimum wages, wage agreements, collective bargaining, and the Labor Board and its powers, primarily falls upon production and not upon commerce; and confirms the further resulting conclusion that production is a purely local activity. It follows that none of these essential antecedents of production constitutes a transaction in or forms any part of interstate commerce. Schechter Corp. v. United States, supra, p. 542 et seq. Everything which moves in interstate commerce has had a local origin. Without, local production somewhere, interstate commerce, as now carried on, would practically disappear. Nevertheless, the local character of mining, of manufacturing and of Crop growing is a fact, and remains a fact, whatever may be done with the products.
Certain decisions of this court, superficially considered, seem to lend support to the defense of the act now under review. But upon examination, they will be seen to be inapposite. Thus, Coronado Coal Co. v. United Mine Workers, 268 U. S. 295, 310, and kindred cases, involved conspiracies to restrain interstate commerce in .violation of the Anti-trust laws. The acts of the persons involved were local in character, but the intent was to restrain interstate commerce, and the means employed were calculated to carry that intent into effect. Interstate commerce was the direct object of attack; and the restraint of such commerce was the necessary consequence of the acts and the immediate end in view. Bedford Stone Co. *305v. Stone Cutters Assn., 274 U. S. 37, 46, The applicable law was concerned not with the character of the acts or of the means employed, which might be in and of themselves purely local, but with the intent and direct operation of those acts and means upon interstate commerce. “The mere reduction in the supply of an article,” this court said in the Coronado Co. case, supra, p. 310, “to be shipped in interstate commerce by the illegal or tortious. prevention of its manufacture or production is ordinarily an indirect and remote obstruction to that commerce. But when the intent of those unlawfully preventing, the manufacture or production is shown to be to restrain or control the supply entering and moving in interstate commerce, or the price of it in interstate markets, their action is a direct violation of the Anti-Trust Act.”
Another group of cases, of which Swift & Co. v. United States, 196 U. S. 375, is an example, rest upon the circumstance that the acts in question constituted direct interferences with the “flow” of commerce among the states. In the Swift case, livestock was consigned and. delivered to stockyards—not as a place of final destination, but, as the court said in Stafford v. Wallace, 258 U. S. 495, 516, “a throat through which the current flows.” The sales which ensued merely changed the private interest in the subject of the current without interfering with its continuity. Industrial Assn. v. United States, 268 U. S. 64, 79. It was nowhere suggested in these cases that the interstate commerce power extended to the growth or production of. the things which, after production, entered the flow. If the court had held that the raising of the cattle, which were involved in the Swift case, including the wages paid to and working conditions of the herders and others employed in the business, could be regulated by Congress, that, decision and decisions holding similarly would be in *306point; for it is that situation, and not the one with which the court actually dealt, which here concerns us.
The distinction suggested is illustrated by the decision in Arkadelphia Milling Co. v. St. Louis S. W. Ry. Co., 249 U. S. 134, 150-152. That case dealt with orders of a state commission fixing railroad rates. One of the questions considered was whether certain shipments of rough material from the forest to mills in the same state for manufacture, followed by the forwarding of the finished product to points outside the state, was a continuous movement in interstate commerce. It appeared that when the rough material reached the mills it was manufactured into various articles which were stacked or placed in kilns to dry, the processes occupying several months. Markets for the manufactured articles were almost entirely in other states or in foreign countries. About 95% of the finished articles was made for outbound shipment. When the rough material was shipped to the mills, it was expected by the mills that this percentage of. the finished articles would be so sold and shipped outside the state. And all of them knew and intended that this 95% of the finished product would be so sold and shipped. This court held that the state order did not interfere with interstate commerce, and that the Swift case was not in point; as it is not in point here:
The restricted field covered by the Swift and kindred cases is illustrated by the Schechter case, supra, p. 543. There the commodity in question, although shipped from another state, had come to rest in the state of its destination, and, as the court pointed -out, was no longer in a current or flow of interstate commerce. The Swift doctrine was rejected as inapposite. In the Schechter casé the flow had ceased. Here it had not begun. The difference is not one of substance. The applicable principle is the same.
*307But § 1 (the preamble) of the act now under review declares that all production and distribution of bituminous coal “bear upon and directly affect its interstate commerce”; and that regulation thereof is imperative for the protection of such commerce. The contention of the government is that the labor provisions of the act may be sustained in that view.
That the production of every commodity intended for interstate sale and transportation has some effect upon interstate commerce may be, if it has not already been, freely granted;- and we are brought to the final and decisive inquiry, whether here that effect is direct, as the .“preamble” recites, or indirect. The distinction is not formal, but substantial in the highest degree, as we pointed out in the Schechter case, supra, p. 546, et seq. “If the commerce clause were construed,” we there said, “to reach all enterprises and transactions which could be said to have an indirect effect upon interstate commerce, the federal authority would embrace practically all the activities of the people and the authority of the State over its domestic.concerns would exist only by sufferance of the federal government. Indeed, on such a theory, even-the development of the State’s commercial facilities would be subject to federal control.” It was also pointed out, p. 548, that “the distinction between direct and indirect effects of intrastate, transactions upon interstate commerce must be recognized as a fundamental one, essential to the maintenance of our constitutional system.”
Whether the effect of a given activity or condition is direct or indirect is not always easy to determine. The-word “direct” implies that the activity or condition invoked or blamed shall operate proximately—not mediately, remotely, or collaterally—to produce the effect. It connotes the absence of an efficient intervening agency *308or condition. And the extent of the effect bears no logical relation to its character. The distinction between a direct and an indirect effect turns, not upon the magnitude of either the cause or the effect, but entirely upon the manner in which the effect has been brought about. If the production by one man of a single ton of coal intended for interstate sale and shipment, and actually so sold and shipped, affects interstate commerce indirectly, the effect does' not become direct by multiplying the tonnage, or increasing the number of men employed, or adding to the expense or complexities of the business, or by all combined. It is quite true that rules of law are sometimes qualified by considerations of degree, as the government argues. But.the matter of degree has no bearing upon the question here, since that question is not—What is the extent of the local activity or condition, or the extent of the effect produced upon interstate commerce? but—What is the relation between the activity or condition and the effect?
Much stress is put upon the evils which come from the struggle between employers and employees over the matter 'of wages, working conditions, the right of collective bargaining, etc., and the. resulting strikes, curtailment and irregularity of production and effect on prices; and it is insisted that interstate commerce is greatly affected thereby. But, in addition to what has just been said, the conclusive answer is that the evils are all local evils over which the federal government has no legislative control. The relation of employer and employee is a local relation. At common law, it is one of the domestic relations. The wages are paid for the doing of local work. Working conditions are obviously local conditions. The employees are not engaged in of about commerce, but exclusively in producing a commodity. And the controversies and. evils, which it is the object of the *309act to regulate and minimize, are local controversies and evils affecting local work undertaken to accomplish that local result. Such effect as they may have upon commerce, however extensive it may be, is secondary and indirect. An increase in the greatness of the effect adds to its importance. It. does not alter its character.
The government’s contentions in defense of the labor provisions are really disposed of adversely by our decision in the Schechter case, supra. The only perceptible difference between that case and this is that in the Schechter case the federal power was asserted with respect to commodities which had come to rest after their interstate transportation; while here, the case deals with commodities at rest before interstate commerce has begun. That difference is without significance. The federal regulatory power ceases when interstate commercial intercourse ends; and, correlatively, the power does not attach until interstate commercial intercourse begins. There is no basis in law or reason for applying different rules to the two situations. No such distinction can be found in anything said in the Schechter case. On the contrary, the situations were recognized as akin. . In the opinion, at page 546, after calling attention to the fact that if the commerce clause could be construed to reach transactions having an' indirect effect upon interstate commerce the federal authority would embrace practically all the activities of the people, and the authority of the state over its domestic concerns would exist only by sufferance of the federal government, we said: “Indeed, on such a theory, even the development of the State’s commercial facilities would be subject to federal control.” And again, after pointing out that hours and wages have no direct relation to interstate commerce and that if the federal government had power to determine the wages and hours of employees in the internal commerce of a ■state because of their relation to cost and prices and their *310indirect effect upon interstate commerce, we said, p. 549: “All the processes of production and distribution that enter into cost could likewise be controlled. If the cost of doing an intrastate business is in itself the permitted object of federal control, the extent of the regulation of cost would be a question of discretion and not of power.” A reading of the entire opinion makes clear, what we now declare, that the want of power on the part of the federal government is the same whether the wages, hours of service, and working conditions, and the bargaining about them, are related to production before interstate commerce has begun, or to sale and distribution after it has ended.
Sixth. That the act, whatever it may be in form, in fact is compulsory clearly appears. We have already discussed § 3, which imposes the excise tax as a penalty to compel “acceptance” of the code. Section 14 provides that the United States shall purchase no bituminous coal produced at any mine where the producer has not complied with the provisions of the code; and that each contract made by the United States shall contain a provision that the contractor will buy no bituminous coal to use on, or in the carrying out of, such contract unless the producer be a member of the code, as certified by the coal commission. In the light of these provisions we come to a consideration of subdivision (g) of Part III of § 4, dealing with “Labor Relations.”
That subdivision delegates the power to fix maximum hours of labor to a part of the producers and the miners— namely, “the producers of more than two-thirds of the annual national tonnage production for the preceding calendar year” and' “more 'than one-half of the miné workers employed”; and to producers of more than two-thirds of the district annual tonnage during the preceding calendar year and a majority of the miners, there is delegated the power to fix minimum wages for the district *311or group of districts. The effect, in respect of wages and hours, is to subject the dissentient minority, either of producers or miners or both, to the will of the stated majority, since, by refusing to submit, the'minority at once incurs the hazard of enforcement of the drastic compulsory provisions of the act to which we have referred. To “accept,” in these circumstances, is not to exercise a choice, but to surrender to force.
The power conferred upon the majority is, in effect, the power to regulate the affairs of an unwilling minority., This is legislative delegation in its most obnoxious form; for it is not even delegation to an official or an official body, presumptively disinterested, but to private persons whose interests may be and often are adverse, to the interests of others in the same business. The record shows that the conditions of competition differ among the various localities. In some, coal dealers compete among themselves. In other localities, they also compete with the mechanical production of electrical energy and of natural gas. Some coal producers favor the code; others oppose it; and the record clearly indicates that this diversity of view arises from their conflicting and even antagonistic interests. The difference, between producing coal and regulating its production is, of course, fundamental. The former is a private activity; the latter is necessarily a governmental function, since, in the very nature of things, one person may not be entrusted! with the power to regulate the business of another, and! especially of 'a competitor. And a statute which attempts to confer such power undertakes an intolerable and unconstitutional interference with personal liberty and private property. The delegation is so clearly arbitrary, and so clearly a denial of rights safeguarded by the due process clause of the Fifth Amendment, that it is unnecessary to do more than refer to decisions of this court which foreclose the question. Schechter Corp. v. United States, *312295 U. S. at p. 537; Eubank v. Richmond, 226 U. S. 137, 143; Seattle Trust Co. v. Roberge, 278 U. S. 116, 121-122.
Seventh. Finally, we are brought to the price-fixing provisions of the code. The necessity of considering the question of their constitutionality will depend upon whether they are separable from the labor provisions so that they can stand independently. Section 15 of the act provides:
“If any provision of this Act, or the application thereof to any person or circumstances, is held invalid, the remainder of the Act and the application of such provisions to other persons or circumstances shall not be affected thereby.”
In the absence of such a provision, the presumption is that the legislature intends an act to be effective as an entirety—that is to say, the rule is against the mutilation of a statute; and if any provision be unconstitutional, the presumption is that the remaining provisions fall with it. The effect of the statute is to reverse this presumption in favor of inseparability and create the opposite one of separability. Under the non-statutory rule, the burden is upon the supporter of the legislation to show the separability of the provisions involved. Under the statutory rule, the.burden is-shifted to the assailant to show their inseparability. But under either rule, the determination, in the end, is reached by applying the same test—namely, What was the intent of the lawmakers?
Under the statutory rule, the presumption must be overcome by considerations which establish “the clear probability that the invalid part being eliminated the legislature would not have been satisfied with what remains,” Williams v. Standard Oil Co., 278 U. S. 235, 241 et seq.; or, as stated in Utah Power & L. Co. v. Pfost, 286 U. S. 165, 184-185, “the clear probability that the legislature would not have been satisfied with the statute un *313less it had included the invalid part.” Whether the provisions of a statute are so interwoven that one being held invalid the-others must fall, presents a question of statutory construction and of legislative intent, to the determination of which the statutory provision becomes an aid. “But it is an aid merely; not an inexorable.command.” Dorchy v. Kansas, 264 U. S. 286, 290. The presumption in favor of separability does not authorize the court to give the statute “an effect altogether different from that sought by the measure- viewed as a whole.” Railroad Retirement Board v. Alton R. Co., 296 U. S. 330, 362.
The statutory aid to construction in no way alters the rule that in order to. hold one part of a statute unconstitutional and uphold another part as separable, they must .not be mutually-dependent upon one another. Perhaps a fair .approach to a solution of the problem is to suppose that while the bill was pending in Congress a motion to strike out the labor provisions had prevailed, and to inquire whether, in that event, the statute should be so construed as to justify the conclusion that Congress, notwithstanding, probably would not have passed the price-fixing provisions of the code.
Section 3 of the act, which provides that no-producer shall, by accepting the code or the drawback of taxes, be estopped from contesting the constitutionality of any provision of the code,- is thought to aid the separability clause. But the effect of that provision is simply to permit the producer to challenge any provision of the code despite his acceptance of the code or the drawback. It seems not to have anything to do with the question of separability.
With the-foregoing .principles in mind, let us examine' the act itself. The title of the act and the preamble demonstrate, as we have already seen, that Congress desired to accomplish certain general purposes therein recited. To that end it created a commission, with man*314datory directions to formulate into a working agreement the provisions set forth in § 4 of the act. That being done, the result is a code. Producers accepting and operating under the code are to be known as code members; and § 4 specifically requires that, in order to carry out the policy of the act, “the code shall contain the following conditions, provisions, and obligations . . .” which are then set forth. No power is vested in the commission, in formulating the code, to omit any of these conditions, provisions, or obligations. The mandate to include them embraces all of them. Following the requirement just quoted, and, significantly, in the same section (International Textbook Co. v. Pigg, 217 U. S. 91, 112-113) under appropriate headings, the price-fixing and labor-regulating provisions are set out in great detail. These provisions, plainly meant to operate together and not separately, constitute the means designated to bring about the stabilization of bituminous-coal production, and thereby to regulate or affect interstate commerce in such coal. The first clause of the title is: “To stabilize the bituminous coal-mining industry and promote its interstate commerce.”
Thus, the primary contemplation of the act is stabilization of the industry through the regulation of labor and the regulation of prices; for, since both were adopted, we must conclude that both were thought essential. The regulations of labor on the one hand and prices on the other furnish mutual aid and support; and their associated force—not one or the other but both combined— was deemed by Congress to be necessary to achieve the end sought. The statutory mandate for a code upheld by two legs at once suggests the improbability that Congress would have assented to a code supported by only one.
This seems plain enough; for Congress must have been conscious of the fact that elimination of the labor provi*315sions from the act would seriously impair, if not destroy, the force and usefulness of the price provisions. The interdependence of wages and prices is manifest; Approximately two-thirds of the cost of producing a ton of coal is represented by wages. Fair prices necessarily depend, upon the cost of production; and since wages constitute so large a proportion of the cost, prices cannot be fixed with any proper relation to cost without taking into consideration this major element. If one of them becomes uncertain, uncertainty with respect to the other necessarily ensues.
So much is recognized by the code itself. The introductory clause of Part III declares that the coriditions respecting labor relations áre “To effectuate the purposes of this Act.” And subdivision (a) of Part II, quoted in the forepart of this opinion, reads in part: “In order to sustain the stabilization of wages, working-conditions, and maximum hours of labor, said prices shall be established so as to yield a return per net ton for each district in a minimum price area, . . . equal as nearly as may be to the weighted average of the total costs, per net ton . . .” Thus wages, hours of labor, and working-conditions are to be so adjusted as to effectuate the purposes of the act; and prices are to be so regulated as to stabilize wages, working conditions, and hours of labor which have been or are to. be fixed under the labor provisions. The two are so woven, together as to render the probability plain enough that uniform prices, in the opinion of Congress, could not be fairly fixed or effectively regulated, without also .regulating these elements of labor which enter so largely into the cost of production.
' These two sets of requirements are not like a collection of bricks,. some of which may be taken away without disturbing the others, but rather are like the interwoven threads, constituting the warp and woof of a fabric, one *316set of which cannot be removed without fatal consequences to the whole. Paraphrasing the words of this court in. Butts v. Merchants Transportation Co., 230 U. S. 126, 133, we inquire—What authority has this court, by construction, to convert the manifest purpose of Congress to regulate production by the mutual operation and interaction of fixed wages and fixed prices into a purpose to regulate the subject by the opération of the latter alone? Are we at liberty to say from the fact that Congress has adopted an entire integrated system that it probably would have enacted a doubtfully-effective fraction of the system? The words of the concurring Opinion in the Schechter case, 295 U. S. at pages 554-555, are pertinent in reply. “To take from, this .code the provisions as to wages and the hours of labor is to destroy it altogether. . . . Wages, and the hours of labor are essential features of the plan, its very bone and sinew. There is no opportunity in such circumstances for the severance of the infected parts in the hope of saving the remainder.” The conclusion is unavoidable that the price-fixing provisions of the code are so related to and dependent upon the labor provisions as conditions, considerations or compensations, as to make it clearly probable that the latter being held bad, the former would not have been passed. The fall of the latter, therefore, carries down with it the former. International Textbook Co. v. Pigg, supra, p. 113; Warren v. Charlestown, 2 Gray [Mass.] 84, 98-99.
The price-fixing provisions of the code are thus disposed of without coming to the question of their constitutionality; but neither this disposition of the matter, nor anything we have said, is to be taken as indicating that the court .is of opinion that these provisions, if separately enacted, could be sustained.
If there be in the act provisions, other than those we have considered, that .may stand independently, the *317question of their validity is left for future determination when, if ever, that question shall be presented for consideration.
The decrees in Nos. 636, 649, and 650 must be reversed and the causes remanded for further consideration in conformity with this opinion. The decree in No. 651 will be affirmed.
It is so ordered.
Separate opinion of
Mr. Chief Justice Hughes.I agree that the stockholders were entitled to bring their suits; that, in view of the question whether any part of the Act could be sustained, the suits were not premature; that the so-called tax is not a real tax, but a penalty; that the constitutional power of the Federal Government to impose this penalty must rest upon the commerce clause, as the Government concedes; that production—in this case' mining—which precedes commerce, is not itself commerce; and that the power to regulate commerce among the several States is not a power to regulate industry within the State.
The power to regulate interstate commerce embraces the power to protect that commerce from injury, whatever may be the "source of the dangers which threaten it, and to adopt any appropriate means to that end. Second Employers’ Liability Cases, 223 U. S. 1, 51. Congress thus has adequate authority to maintain the orderly conduct of interstate commerce and to provide for the peaceful settlement of disputes which threaten it. Texas & N. O. R. Co. v. Railway Clerks, 281 U. S. 548, 570. But Congress may not use this protective authority as. a pretext for the exertion of power to regulate activities and relations within the States which affect interstate commerce only indirectly. Otherwise, in view of the multitude of indirect effects, Congress in its discretion *318could assume control of virtually all. the activities of the people to the subversion of the fundamental principle of the Constitution. If the people desire to give Congress the power to regulate industries within the State, and the relations of employers and employees in those industries, they are at liberty to declare their will in the appropriate manner, but it is not for the Court to amend the Constitution by judicial decision.
I also agree that subdivision (g) of Part III of the prescribed Code is invalid upon three counts: (1) It attempts a broad delegation of legislative power to fix hours and wages without standards or limitation. The Government invokes the analogy of legislation which becomes effective on the happening of a specified event, and says that in this case the event is the agreement of a certain proportion of producers and employees, whereupon the other producers and employees become subject to legal obligations accordingly. I think that the argument is unsound and is pressed to the point where the principle would be entirely destroyed. It would remove all restrictions upon the delegation of legislative power, as the making of laws could thus be referred to any designated officials or private persons whose orders or agreements would be treated as “events,” with the result that they would be invested with the force of law having penal sanctions. (2) The provision permits a group of producers and employees, according to tlieir own views of expediency, to make rules as to hours and wages for other producers and employees who were not parties to the agreement. Such a provision, apart from the mere question of the delegation of legislative power, is not in accord with the requirement of due process of law which under the Fifth Amendment dominates the regulations which Congress may impose. (3) The provision goes beyond any proper measure of protection of interstate *319commerce and attempts a broad regulation of industry within the State.
But that is not the whole case. The Act also provides for the regulation of the prices of bituminous coal sold in interstate commerce and prohibits unfair methods of competition in interstate commerce. Undoubtedly transactions in carrying on interstate commerce are subject to the federal power to regulate that commerce and the control of charges and the protection of fair competition in that commerce are familiar illustration's of the exercise of the power, as the Interstate Commerce Act, the Packers and Stockyards Act, and the Anti-Trust Acts abundantly show. The Court has repeatedly stated that the power to regulate interstate commerce among the several States is supreme and plenary. Minnesota Rate Cases, 230 U. S. 352, 398. It is “complete in itself, and may be exercised to its utmost extent, and acknowledges no limitations, other than are prescribed in the Constitution.” Gibbons v. Ogden, 9 Wheat. 1, 196. We are not at liberty to deny to the Congress, with respect to interstate commerce, a power commensurate with that enjoyed by the States in the regulation of their internal commerce. See Nebbia v. New York, 291 U. S. 502.
Whether the policy of fixing prices of commodities sold in interstate commerce is a sound policy is not for our consideration. The question of that policy, and of its particular applications, is for Congress. The .exercise of the power of regulation is subject to the constitutional restriction of the due process clause, and if in fixing rates, prices or conditions of competition, that requirement is transgressed, the judicial power may be invoked to the end that the constitutional limitation may be maintained. Interstate Commerce Comm’n v. Union Pacific R. Co., 222 U. S. 541, 547; St. Joseph Stock Yards Co. v. United States, ante, p. 38.
*320In the legislation before us, Congress has set up elaborate machinery for the fixing of prices of bituminous coal sold in interstate commerce. That provision is attacked in limine. Prices have not yet been fixed. If fixed, they may not be contested. . If contested, the Act provides for review of the administrative ruling. If in fixing prices, due process is violated by arbitrary, capricious or confiscatory action, judicial remedy is available. If an attempt is made to fix prices for sales in intrastate commerce, that attempt will also be subject to attack by appropriate action. In that relation it should be noted that in the Carter cases, the court below found that substantially all the coal mined by the Carter Coal Company is sold f. o. b. mines and is transported into States other than those in which it is produced for the purpose of filling orders obtained from purchasers in such States. Such transactions are in interstate commerce. Savage v. Jones, 225 U. S. 501, 520. The court below also found that “the interstate distribution and sale and the intrastate distribution and sale” of the coal are so “intimately and inextricably connected” that “the regulation of interstate transactions of distribution and sale cannot be accomplished effectively without discrimination against interstate commerce unless transactions of intrastate distribution and sale be regulated.” Substantially the same situation is disclosed in the Kentucky cases. In that relation, the Government invokes the analogy of transportation rates. Shreveport Case, 234 U. S. 342; Wisconsin Railroad, Comm’n v. Chicago, B. & Q. R. Co., 257 U. S. 563. The question will be the subject of consideration when it arises in any particular application of the Act.
• Upon what ground, then, can it be said that this plan for the regulation of transactions in interstate commerce in coal is beyond the constitutional power of Congress? The Count reaches that conclusion in the view that the *321invalidity of the labor provisions requires us to condemn the Act in its entirety. I am unable to concur in that opinion. I think that the express provisions of the Act preclude such a finding of inseparability.
This is admittedly a question of statutory construction; and hence we must search for the intent of Congress. And in seeking that intent we should not fail to give full weight to what Congress itself has said upon the very point. The Act provides (§ 15):
“If any provision of this Act, or the application thereof to any person or circumstances, is held invalid, the remainder of the Act and the application of such provisions to other persons or circumstances shall not be affected thereby.”
That is a flat declaration against treating the provisions of the Act as inseparable. It is a declaration which Congress was competent to make. It is a declaration which reverses the presumption of indivisibility and creates an opposite presumption. Utah Power & Light Co. v. Pfost, 286 U. S. 165, 184.
The above quoted provision does not stand alone. Congress was at pains to make a declaration of similar import with respect to the provisions of the Code (§ 3):
“No producer shall by reason of his acceptance of the code provided for in section 4 or of the drawback of taxes provided in section 3 of this Act .be held to be precluded or estopped from contesting the constitutionality of any provision of said code, or its validity as applicable to such producer.”
This provision evidently contemplatés, when read with the one first quoted, that a stipulation of the Code may be found to be unconstitutional and yet that its invalidity shall not be regarded as affecting the obligations attaching to the remainder.
■ I do not think that the question of separability should be determined by trying to imagine what Congress would *322have done if certain provisions found to be invalid were excised. That, if taken broadly, would lead us into a realm of pure speculation. Who can tell amid the host of divisive influences playing upon the legislative body what its reaction would have been to a particular excision required by a finding of invalidity? The question does not call for speculation of that sort but rather for an inquiry whether the provisions are inseparable by virtue of inherent character. That is, when Congress states that the provisions of the Act are not inseparable and that the invalidity of any provision shall not affect others, we should not hold that the provisions are inseparable unless their nature, by reason of an inextricable tie, demands that conclusion.
All that is said in the preamble of the Act, in the directions to the Commission which the Act creates, and in the stipulations of the Code, is subject to the explicit direction of Congress that the provisions of the statute shall not be treated as forming an indivisible unit. The fact that the various requirements furnish to each other mutual aid and support does not establish indivisibility: The purpose of Congress, plainly expressed, was that if a part of that aid were lost, the whole should not be lost. Congress desired that the Act and Code should be operative so far as they met the constitutional test. Thus we are brought, as I have said, to the question whether, despite this purpose of Congress, we must treat the marketing provisions and the labor provisions as inextricably tied together because of their nature. I find no such tie. The labor provisions are themselves separated and placed in a separate part (Part III) of the Code. It seems quite clear that the validity of the entire Act cannot depend upon the provisions as to hours and wages in paragraph (g) of Part III. For what was contemplated by that paragraph is manifestly independent of *323the other machinery of the Act, as it cannot become effective unless the specified proportion of producers and employees reach an agreement as to particular wages and hours. And the provision for collective bargaining in paragraphs (a) and (b) of Part III is apparently made separable from the Code itself by § 9 of the Act, providing, in substance, that the employees of all producers shall have the right of collective bargaining even when producers do not accept or maintain the Code.
The marketing provisions (Part II) of the Code naturally form a separate category. The interdependence of wages and prices is no clearer in the coal business than in transportation. But the broad regulation of rates in order to stabilize transportation conditions has not carried with it the necessity of fixing wages. Again, the requirement, in paragraph (a) of Part II that district boards shall establish prices so as to yield a prescribed “return per net ton” for each district in a minimum price area, in order “to sustain the stabilization of wages, working conditions and maximum hours of labor,” does not link the marketing provisions to the labor provisions by an unbreakable bond. Congress evidently desired stabilization through both the provisions relating to marketing and those relating to labor, but the setting up of the two sorts of- requirements did not make the one dependent upon the validity of the other. It is apparent that they are not so interwoven that they cannot have separate operation and effect. The marketing provisions in relation to interstate commerce can be carried out as provided in Part II without regard to the labor provisions contained in Part III. That fact, in the light of the congressional declaration of separability, should be considered of controlling importance.
In this view, the Act, and the Code for which it provides, may be sustained in relation to the provisions for *324marketing' in interstate commerce, and the decisions of the courts below, so far as they accomplish that result, should be affirmed.