Mr. Justice White
delivered the opinion of the court.1
To dispose of these cases it is necessary to decide a fundamental question which is equally decisive as to both. They were argued at the bar together, and because of their unity have been considered at the same time.
As stated in the declarations as finally amended, recovery was sought in each case of damages occasioned by the death of the respective intestates while serving as a fireman on a locomotive actually engaged in moving an interstate commerce train. In each of the cases it was alleged that the intestate met his death through no fault of his, but solely through the fault of employés of the company, who were his fellow servants. In both the right of action was expressly based upon the act of Congress of July 11, 1906, entitled “An Act relating to liability of common Carriers in the District of Columbia and Territories and common carriers engaged in commerce between the States and between the States and foreign nations to their employés.” By demurrer in each of the cases the act relied upon was assailed as being repugnant to the Constitution of [490]*490the United States. In both cases the Department of Justice, on behalf of the United States, asked to be allowed to intervene for the purpose of supporting the constitutionality of the act. In the first (the Howard) ease this request was granted. In the second (the Brooks) case the court, while denying the request upon the ground that it knew of no law authorizing such ■an. intervention simply because, the validity of an act of Congress was drawn in question, nevertheless permitted the United States to be heard as a friend of the court. In both cases the act was held to be unconstitutional, the demurrer was sustained and the declarations dismissed. These direct writs of error were then prosecuted, and at bar the cases have been argued, by printed brief and orally, not only by the parties in interest, but on behalf of the United States through the Attorney General as a friend of the court.
As the issue to be decided is whether the courts below were right in holding that the act of Congress, which was the basis of the respective causes of action, was repugnant to the Constitution of the United States, we reproduce the text of that act in the margin.1
[491]*491Before coming to consider the contentions concerning the constitutionality of the act, we notice certain suggestions which proceed upon the assumption that they may concern the issue for decision. It is said that the statute inordinately extends the power of Congress and unduly diminishes the legislative authority of the States, since it seeks to exert the pouc of Congress as to the relation of master and servant, a subject hitherto treated as being exclusively within the control of the States, and that in practice its execution will cripple the State and enlarge the Federal judicial power, since its effect will be to cause every action concerning an injury to a servant employed by a common carrier who may engage, in interstate commerce to cease to be a matter of state jurisdiction and to be cognizable in the Federal courts. Moreover, it is said, the statute will create confusion and uncertainly as to the rights of those dwelling within the States, that it will operate injuriously upon all who choose to engage in interstate commerce [492]*492as a common carrier, since those who so do will become subject to the liability which the statute creates, to be tested by the rules of negligence which the statute embodies, although such rules be unknown to the laws of the several States. Besides, the. statute, it is urged, discriminates against all who engage as- common carriers in interstate commerce, since it makes them responsible without limit as to the amount to one servant for an injury suffered by the acts of a co-servant, even in a case where the negligence of the injured servant has contributed to the result, hence placing all employers who are common carriers in a disfavored and all their employés in a favored class. Indeed it is insisted the statute proceeds upon contradictory principles, since it imposes the increased responsibility just stated upon the master presumably in order to make Kim more careful in the selection of his servants, and yet minimizes the necessity for care on the part of the servant by allowing recovery, although he may have been negligent.
But, without even for the sake of argument conceding the correctness of these suggestions, we at once dismiss them from consideration as concerning merely the expediency of the act and not the power of Congress to enact it. We say this since, in testing the constitutionality of the act, we must confine ourselves to the power to pass it and may not consider evils which it is supposed will arise from the execution of the law, whether they be real or imaginary.
All the questions which arise concern the nature and extent of the power of Congress to regulate commerce. That subject has been so often here considered and has been so fully elaborated in recent decisions, two of which are noted in the margin,1 that we content ourselves, for the purposes of this case, with repeating the broad definition of the commerce power as expounded by Mr. Chief Justice Marshall in Gibbons v. Ogden, 9 Wheat. 1,196, where he said:
“We are now arrived at the inquiry, What is this power? [493]*493It is the power to regulate; that is, to prescribe the rule by which commerce is to be governed. This power, like all others vested in Congress, is complete in itself, may be exercised to its utmost extent, and acknowledges no limitations other than are prescribed in the Constitution. .... . If, as has always been understood, the sovereignty of Congress, though limited to specified objects, is plenary as to those objects, the power over' commerce with foreign nations, and among the several States, is vested in Congress as absolutely as it would be in a single government, having in its constitution the'same restrictions, on the exercise of the power as are found in the Constitution of the United States.”
Accepting, as we now do and as has always been done, this comprehensive statement of the power of Congress, we also adopt and reiterate the. perspicuous statement made in the same case (p. 194},.of those matters of state' control which are not embraced in the grant of authority to Congress to regulate commerce:
“It is not intended to say that these woxus comprehend that commerce, which is completely internal, which is carried on between man and man in a State, or between different parts of the same State, and which does not extend to or affect other States. Such a power would be inconvenient and is certainly unnecessary. Comprehensive as the word 'among’ is, it may very properly be restricted to that commerce which concerns more States than one. . . . The genius and character of the whole Government seem to be, that its action is to be applied to all the external concerns of the Nation, and to those internal concerns which affect the States generally; but not to those which are completely within a particular State, which do not affect other States, and with wdiich it is not necessary to interfere, for the purpose of executing some of the general powers of the Government.” ■
We think the orderly discussion of the question may best be met oy disposing of the affirmative propositions relied on to establish that ’the statute conflicts with the Constitution.
[494]*494In the first place, it is asserted that there is a total want of power in Congress in any conceivable aspect to regulate the subject with which the act deals. In the second place it is insisted the act is void, even although it be conceded, for the sake of argument, that some phases of the subject with which it is concerned may be within the power of Congress, because the act is confined not to such phases,, but asserts control over many things not in any event within the power to regulate commerce.
While it may be, if we indulged, for the sake of argument, in the hypothesis of limited power upon which the second proposition rests, it would result that a consideration of the first proposition would be unnecessary because the act would be found to be repugnant to the Constitution, because embracing provisions beyond such assumed and restricted authority we do not think we are at liberty to avoid deciding whether, in any possible aspect, the subject to which the act relates is within the power of Congress. We say this, for if it be that from the nature of the subject no power whatever over the same can, under any conceivable circumstances, be possessed by Congress, we ought to so declare, and not by an attempt to conceive the inconceivable assume the existence of some authority, thus it may be, misleading Congress and giving rise to future contention.
.1. The proposition that there is an absolute want of power in Congress to enact the statute is based on the assumption that as the statute is solely addressed to the regulation of the relations of the employer to those whom he employs and the relation of those employed by 'him among themselves, it deals with subjects which cannot under any circumstances come within the power conferred upon Congress to regulate commerce.
As it is patent that the act does regulate the relation of master and servant in. the cases to which it applies, it must follow, that the act is beyond the authority of Congress if the proposition just stated be well founded. But we may not [495]*495test the power of Congress to regulate commerce solely by abstractly considering the particular subject to which a regulation relates, irrespective of whether the regulation in question is one of interstate commerce. On the contrary, the test of power is not merely the matter regulated, but whether the regulation is directly one of interstate commerce, or is embraced within the grant conferred on Congress to use all lawful means necessary and appropriate to the execution of the power to regulate commerce. We think the unsoundness of the contention, that because the act regulates the relation of master and servant, it is unconstitutional, because under no circumstances and to no extent can the regulation of such subject be within the -grant of authority to regulate commerce, is demonstrable. We say. this because we fail to perceive any just reason for holding that Congress is without power to regulate the relation of, master and servant, to the extent that regulations adopted by Congress on that subject are solely confined to interstate commerce, and therefore are within the grant to regulate that commerce or within the authority given to use all means appropriate to the exercise of the powers conferred. To illustrate: Take the case of an interstate railway train, that is, a train moving in interstate commerce, and the regulation of which therefore is, in the nature of things, a regulation of such commerce. It cannot be said that because a regulation adoptéd by Congress as to such train when so engaged in interstate commerce deals with the relation of the master* to the servants operating such train or the relations of the servants engaged in such operation between themselves, that it is not a regulation of interstate commerce. This must be, since to admit the authority to regulate such train, and yet to sáy that all regulations which deal with the relation of master and servants engaged in its operation are invalid for want of power would be but to concede the power and then to deny it, or at all events to recognize the power and yét to render it incomplete.
Because of. the reasons just stated we might well pass from the consideration of the subject. We add, however, that we [496]*496think the error of the proposition is shown by previous decisions of this court. Thus the. want of power in a State to interfere with an interstate commerce train, if thereby a direct burden is imposed upon interstate commerce, is settled beyond ■ question. Mississippi R. R. Co. v. Illinois Cent. R. R., 203 U. S. 335, 343, and cases cited; Atlantic Coast Line R. R. v. Wharton et al., Railroad Commissioners, 207 U. S. 328. And decisions cited in the margin,1 holding that state statutes which regulated the relation of master and servant were applicable to those actually engaged in an operation of interstate commerce, because the state power existed until Congress acted, by necessary implication, refute the contention that a regulation of the subject, confined to interstate commerce, when adopted by Congress would be necessarily void because the regulation of the relation of master and servant was, however intimately connected with interstate commerce, beyond the power of Congress. And a like conclusion also persuasively results from previous rulings of this court concerning the act of Congress, known as the Safety Appliance Act. Johnson v. Southern Pacific Co., 196 U. S. 1; Schlemmer v. Buffalo, Rochester &c. Ry., 205 U. S. 1.
2. But it is argued, even though it be conceded that the power of Congress may be exercised as to the relation of master and servant in .matters of interstate commerce, that power cannot be lawfully extended so as to include the' regulation of the relation of master and servant, or of servants among themselves, as to things which are not interstate commerce: From this it is insisted the repugnancy of the act to the Constitution is clearly shown, as the face of the act makes it certain that the power which it asserts extends not only to the relation, of master and servant and servants among themselves as to things which are wholly interstate commerce, but em[497]*497braces those relations as to matters and things domestic in their character and which do not come within the authority of Congress. To test this proposition requires us to consider the text óf the act.
From the first section it is certain that the act extends to every individual or corporation who may engage in interstate commerce as a common carrier. Its all-embracing words leave no room for any other conclusion. It may include, for example, steam railroads, telegraph lines, telephone lines, the express business, vessels of every kind, whether steam or sail, ferries, bridges, wagon lines, carriages, trolley lines, etc. Now, the rule which the statute establishes for the purpose of determining whether all the subjects to which it relates are to be controlled by its provisions is that any one who conducts such business be a “ common carrier engaged in trade or commerce in the District of Columbia, or in any Territory of the United States, or between the several States,” etc. ' That is, the subjects stated all come, within the statute when the individual or corporation is a common carrier who engages in trade or commerce between the States, etc. From this it follows that the statute deals with all the concerns of the individuals or corporations to which it relates if they engage as common carriers in trade or commerce between the States, etc., and does not confine itself to the interstate commerce business which may be done by such persons. Stated in another form, the statute is addressed to the individuals or corporations who are engaged in interstate commerce and is not confined- solely to regulating the interstate commerce business which such persons may do— that is, it regulates the persons because they engage in interstate commerce and does not alone regulate the business of interstate commerce.
And the conclusion thus stated, which flows from the text of the act concerning the individuals or corporations to which it is made to apply, is further demonstrated by a consideration of the text of the statute defining the servants to whom it relates.
[498]*498Thus the liability of a common carrier is declared to be in favor of “any of its employés.” As the word “any” is unqualified, it follows that liability to the servant is coextensive with the business done by the employers whom the statute embraces; that is, it is in favor of any of the employés of all carriers who engage in interstate commerce. This also is the rule as to the one who otherwise would be a fellow servant, by whose negligence the injury or death may have been occasioned, since it is provided that the right to recover on the part of any servant will exist, although the injury for which the carrier is to be held resulted from “ the negligence of any of its officers, agents or employés.”
The act then being addressed to all common carriers engaged in interstate commerce, and imposing a liability upon them in favor of any of their.employés, without qualification or restriction as to the business in which the carriers or their employés may be engaged at the. time of the injury, of necessity includes subjects wholly outside .of the power of Congress to regulate commerce. Without stopping to consider the nu.merous instances where although a common carrier is engaged in interstate commerce such carrier may in.,the nature of things also transact business npt interstate commerce, although such local business may indirectly be related to interstate commerce, a few illustrations showing the operation of the statute as to matters wholly independent of interstate commerce will serve to make clear the extent of the power which is exerted by the statute. Take a railroad engaged in interstate commerce, having a purely local branch operated wholly within a State. Take again the same road having shops for repairs, and it may be for construction work, as well as a large accounting and clerical force, and having, it may be, storage ele.vators and warehouses, not to suggest besides the possibility of its being engaged in other independent enterprises. Take a telegraph company engaged in the transmission of interstate and local messages. Take an express company engaged in local as well as .in interstate business.. Take a trollev line [499]*499moving wholly within a State as to a large part of its business and yet as to the remainder crossing the state line.
As the act thus includes many subjects wholly beyond the power to regulate commerce and depends for its sanction upon that authority, it results that the act is repugnant to the Constitution, and cannot be enforced unless, there be 'merit in the propositions advanced tó show that the statute may be saved.
On the one hand, while conceding that the act deals with all common carriers who are engaged in interstate commerce because they so engage, and indeed, while moreover conceding that the act was originally drawn for the purpose of reaching all the employés of railroads engaged in interstate commerce to which it is said the act in its original form alone related, it is yet insisted that the act is within the power of Congress, because one who engages in interstate commerce thereby comes under the power of Congress as to all his business and may not complain of any regulation which Congress may choose to adopt. These contentions are thus summed up in the brief filed on behalf of the Government:
“ It is the carrier and not its employés that the act seeks to regulate, and the carrier is subject to such regulations because it is engagéd in interstate commerce.
^ ^ «t# ^ ^
“ By engaging in interstate commerce the carrier chooses to subject itself and its business to the control of Congress, and cannot be heard to complain of such regulations.
“. . ■. It is submitted that Congress can make a common carrier engaged in interstate commerce liable to any one for its negligence who is affected by it; and if it can do that, necessarily it can make such carrier liable to all of its employés.”
On the other hand, the same brief insists that these propositions are irrelevant, because the statute may be interpreted so as to confine its operation wholly to interstate commerce or to means appropriate to the regulation of that subject, and hence relieves from -the necessity of deciding whether, if the statute could not be so construed, it would be constitutional. [500]*500In the oral discussion at bar this latter view was earnestly insisted upon by the Attorney General. • Assuming, as' we do, that the propositions are intended to be alternative, we disregard the order in which they are pressed-in argument, and therefore pass for a moment the consideration of the proposition that the statute is constitutional, though it includes all the subjects Which we have found it to embrace, in order to weigh the contention that it is susceptible on its face of a different meaning from that which we have given it, or that such result pan be accomplished by the application of the rules of interpretation which are relied upon.
So far as the face of the statute is concerned, the argument is this,' that because the statute says carriers engaged in commerce between the States, etc., therefore the act should be interpreted as being exclusively applicable to the interstate commerce business and none other of such carriers, and that the words “any employé” as found in the statute should be held to mean any employé when such employé is engaged only in interstate commerce. But this would require us to write into the statute words of limitation and restriction not found in it. But if we could bring ourselves to modify the statute by writing in the words suggested the result would be to restrict the operation of the act as to the District of Columbia and the Territories. We say this because immediately preceding the provision of the act concerning carriers engaged in commerce between the States and Territories is a clause making it applicable to “every common carrier engaged in trade or commerce in the District of Columbia or in any Territory of.the United States.” It follows, therefore, that common carriers in such Territories, even although not engaged in interstate commerce, are by the act made liable to “any” of their employés, as therein defined. The legislative power of Congress over the District of Columbia and the Territories being plenary and not depending upon the'interstate commerce clause, it results that the provision as to the District of Columbia and the Territories, if standing alone, could not be ques[501]*501tionecL Thus it would come to pass, if we could bring ourselves to modify the statute by writing in the words suggested; that is, by causing the act to read "any employé when engaged in interstate commerce,” we would restrict the act as to the District of Columbia and the Territories, and thus destroy it in an important particular. To write into the act the qualifying words, therefore, would be but adding to its provisions in order to save it in one aspect, and thereby to destroy it in another; that is, to destroy in order to save and to save in order to destroy.
The principles of construction invoked are -undoubted, but are inapplicable. Of course, if it can be lawfully done, our duty is to construe the statute so as to render it constitutional. But this does not imply, if the text of an act is unambiguous, that it may be rewritten to accomplish that purpose. Equally clear is it, generally speaking, that where a statute contains provisions which are constitutional and others which are not, effect may be given to the legal provisions by separating them from the illegal. But this applies only to a case where the provisions are separable and not dependent one upon the other, and does not support the contention that that which is indivisible may be divided. Moreover, even in a case where legal provisions may be severed from those which are illegal, in order to save the rule applies only where it is plain that Congress would have enacted the legislation 'with the unconstitutional provisions eliminated. All these principles are so clearly settled as not to be open to controversy. They were all, after a full review of the authorities, restated and reapplied in a recent case. Illinois Central Railroad v. McKendree, 203 U. S. 514, and authorities there cited.
As the act before us by its terms relates to every common carrier engaged in interstate commerce and to any of the employes of every such carrier, thereby regulating every relation of a carrier engaged in interstate commerce with its servants and of such servants among themselves, we are unable to say that the statute would have been enacted had its provisions [502]*502been restricted to the limited relations of that character which it was within the power of Congress to regulate. On this subject the opinion in the Trade-mark Cases, 100 U. S. 82, where an act of Congress concerning trade-marks was held to be unconstitutional, because too broad in its scope, is pertinent and instructive. The court said (p. 99):
“If we should, in the case before us, undertake to make by judicial construction a law which Congress did not make, it is quite probable we should do what, if the matter were now before that body, it would be unwilling to do; namely, make a trade-mark law which is only-partial in its operation, and which would complicate the rights which parties would hold, in some instances under the act of Congress, and in others under state law. Cooley, Const. Lim. 178, 179; Commonwealth v. Hitchings, 5 Gray (Mass.), 482.”
3. It remains only to consider the contention which we have previously quoted, that the act is constitutional, although it embraces subjects not within the power of Congress to regulate commerce, because one who engages in interstate commerce thereby submits all his business concerns to the regulating-power of Congress. To state the proposition is to refute it. It assumes that because one engages in interstate commerce he thereby endows Congress with power not delegated to it by the Constitution, in other words, with the right to legislate concerning matters of purely state concern. It rests upon the conception that the Constitution destroyed that freedom of commerce which it was its purpose to preserve, since it treats the right to engage in interstate commerce as a privilege which cannot be availed of except upon such conditions as Congress may prescribe, even although the conditions would be otherwise beyond the power of Congress. It is apparent that if the contention were well founded it would extend the power of Congress (o every conceivable subject, however inherently local, would obliterate all the limitations of power imposed by the Constitution, and would destroy the authority of the ¡States as to all conceivable matters which from the beginning [503]*503have been, and must continue to be, under their control- so long as the Constitution endures.
4. Reference was made to the report of a committee submitted to the House of Representatives on the coming in of the bill which finally became the act in question. We content ourselves on this subject with saying that that report, we think, instead of adding force to the argument that the plain terms of the act should be disregarded, tends to the contrary. And the same observation is appropriate to the reference made to the text of the Safety Appliance Act of March 2, 1893, 27 Stat. 531, which, it is insisted, furnishes a guide which, if followed, would enable us to disregard the text of the act. We say this because the face of that act clearly refutes the argument based upon it. It is true that the act, like the one we are considering, is addressed to every common carrier engaged in interstate commerce, but this direction is followed by provisions expressly limiting the scope and effect of the act to interstate commerce, which are wholly superfluous if the argument here made concerning the statute before us be sound;
We deem it unnecessary to pass upon the merits of the contentions "concerning the alleged repugnancy of the statute, if regarded as otherwise valid, to the due process clause of the Fifth Amendment to the Constitution, because the act classifies together all common carriers. Although we deem it unnecessary to consider that subject, it must not be implied that we question the correctness of previous decisions noted in the margin,1 wherein state statutes were held not to be repugnant to the Fourteenth Amendment, although they classified steam railroads in one class for the purpose of applying a rule of master and servant. We further deem it unnecessary to express an opinion concerning the alleged repugnancy of the statute to the Seventh Amendment, because of the provision of the act as to the power of the jury. In saying this, however, we must not be considered as intimating that we think [504]*504the provision in question is susceptible of the construction placed on it in argument, or that- if it could be so construed it would be constitutional. •
Concluding, as we do, that the statute, whilst it embraces subjects within the' authority of Congress .to regulate commerce, also includes subjects not within its constitutional power, and that the two are so interblended in thé statute that they are incapable of separation, we are of the opinion that the courts below rightly held the statute to be repugnant to the Constitution and non-enforcible; and the judgments below are, therefore,
Affirmed.
Mb. Justice Day concurs in this opinion.