Mr. Chief Justice TAFT delivered the opinion of the Court.

[1] This case presents the question of the constitutional validity of the Child Labor Tax Law. The plaintiff below, the Drexel Furniture Company, is engaged in the manufacture of furniture in the Western district of North Carolina. On September 20, 1921, it received a notice from Bailey, United States collector of internal revenue for the district, that it had been assessed $6,312.79 for having during the taxable year 1919 employed and permitted to work in its factory a boy under 14 years of age, thus incurring the tax of 10 per cent. on its net profits for that year. The company paid the tax under protest, and, after rejection of its claim for a refund, brought this suit.

**

[2] The law is attacked on the ground that it is a regulation of the employment of child labor in the states—an exclusively state function under the federal Constitution and within the reservations of the Tenth Amendment. It is defendant on the ground that it is a mere excise tax levied by the Congress of the United States under its broad power of taxation conferred by section 8, article 1, of the federal Constitution. We must construe the law and interpret the intent and meaning of Congress from the language of the act. The words are to be given their ordinary meaning unless the context shows that they are differently used. Does this law impose a tax with only that incidental restraint and regulation which a tax must inevitably involve? Or does it regulate by the use of the so-called tax as a penalty?

[3] If a tax, it is clearly an excise. If it were an excise on a commodity or other thing of value, we might not be permitted under previous decisions of this court to infer solely from its heavy burden that the act intends a prohibition instead of a tax. But this act is more. It provides a heavy exaction for a departure from a detailed and specified course of conduct in business. . . If an employer departs from this prescribed course of business, he is to pay to the government one-tenth of his entire net income in the business for a full year. The amount is not to be proportioned in any degree to the extent or frequency of the departures, but is to be paid by the employer in full measure whether he employs 500 children for a year, or employs only one for a day. Moreover, if he does not know the child is within the named age limit, he is not to pay; that is to say, it is only where he knowingly departs from the prescribed course that payment is to be exacted. Scienters are associated with penalties, not with taxes. The employer’s factory is to be subject to inspection at any time not only by the taxing officers of the Treasury, the Department normally charged with the collection of taxes, but also by the Secretary of Labor and his subordinates, whose normal function is the advancement and protection of the welfare of the workers. In the light of these features of the act, a court must be blind not to see that the so-called tax is imposed to stop the employment of children within the age limits prescribed. Its prohibitory and regulatory effect and purpose are palpable.

**

[4] Out of a proper respect for the acts of a co-ordinate branch of the government, this court has gone far to sustain taxing acts as such, even though there has been ground for suspecting, from the weight of the tax, it was intended to destroy its subject. But in the act before us the presumption of validity cannot prevail, because the proof of the contrary is found on the very face of its provisions. . . To give such magic to the word ‘tax’ would be to break down all constitutional limitation of the powers of Congress and completely wipe out the sovereignty of the states.

[5] The difference between a tax and a penalty is sometimes difficult to define, and yet the consequences of the distinction in the required method of their collection often are important. Where the sovereign enacting the law has power to impose both tax and penalty, the difference between revenue production and mere regulation may be immaterial, but not so when one sovereign can impose a tax only, and the power of regulation rests in another. Taxes are occasionally imposed in the discretion of the Legislature on proper subjects with the primary motive of obtaining revenue from them and with the incidental motive of discouraging them by making their continuance onerous. They do not lose their character as taxes because of the incidental motive. But there comes a time in the extension of the penalizing features of the so-called tax when it loses its character as such and becomes a mere penalty, with the characteristics of regulation and punishment. Such is the case in the law before us. Although Congress does not invalidate the contract of employment or expressly declare that the employment within the mentioned ages is illegal, it does exhibit its intent practically to achieve the latter result by adopting the criteria of wrongdoing and imposing its principal consequence on those who transgress its standard.

[6] The case before us cannot be distinguished from that of Hammer v. Dagenhart. Congress there enacted a law to prohibit gransportation in interstate commerce of goods made at a factory in which there was employment of children within the same ages and for the same number of hours a day and days in a week as are penalized by the act in this case.

**

[7] The analogy of the Dagenhart Case is clear. The congressional power over interstate commerce is, within its proper scope, just as complete and unlimited as the congressional power to tax, and the legislative motive in its exercise is just as free from judicial suspicion and inquiry. Yet when Congress threatened to stop interstate commerce in ordinary and necessary commodities, unobjectionable as subjects of transportation, and to deny the same to the people of a state in order to coerce them into compliance with Congress’ regulation of state concerns, the court said this was not in fact regulation of interstate commerce, but rather that of state concerns and was invalid. So here the so-called tax is a penalty to coerce people of a state to act as Congress wishes them to act in respect of a matter completely the business of the state government under the federal Constitution. This case requires as did the Dagenhart Case the application of the principle announced by Chief Justice Marshall in McCulloch v. Maryland, 4 Wheat. 316, 423 (4 L. Ed. 579), in a much-quoted passage: ‘Should Congress, in the execution of its powers, adopt measures which are prohibited by the Constitution; or should Congress, under the pretext of executing its powers, pass laws for the accomplishment of objects not intrusted to the government; it would become the painful duty of this tribunal, should a case requiring such a decision come before it, to say that such an act was not the law of the land.’

**

[8] For the reasons given, we must hold the Child Labor Tax Law invalid.

**