upon such as are brought into it for sale; and it is most usually levied or secured before the importer is allowed to exercise his right of ownership over them, because evasions of the law can be more certainly prevented by executing it whilst the articles are in its custody..

800. It would not, however, be less a duty on the articles, if it were levied on them after they were landed; as the policy and practice of levying and securing the duty before, or upon, entering the port, does not limit the power to that period for its exercise; and consequently the prohibition upon the exercise of such a power, is not so limited, unless the meaning of the term so confines it.

801. Imports are things imported, or the articles themselves which are brought into the country; and a duty on imports, is not merely a tax on the act of importation, but an impost on the thing imported; and is not confined in its signification to a duty levied whilst the article is entering the country, but extends to a duty levied after the article has actually entered it.

802. There is no difference in effect between a power to prohibit the sale of an article, and a power to prohibit its introduction into the country; and the one would be the necessary consequence of the other, as no goods would be imported, if none could be sold; nor can any object be accomplished by laying a duty upon importation, which may not be effected by laying a duty on the article, in the hands of the importer.

803. The prohibition on the States to lay a duty on imports, may, indeed, come in conflict with their acknowledged powers to tax persons and property

within their jurisdiction; but the right which an importer acquires, not only to bring the articles into the country, but to mix them by sale with the common mass of property, does not interfere materially with the necessary power of taxation acknowledged to reside in the States.

804. When the importer has so dealt with the thing imported, as that it has become incorporated with the mass of property in the country, it has perhaps lost its distinetive character as an import, and become subject to the taxing power of the State; -but whilst it continues the property of the importer and remains in his warehouse, a State tax on it, is a duty on imports within the prohibition.

805. Although a State may lay a tax on occupations, yet in the instance of an importer, of foreign goods, it makes no difference that the tax is imposed on the person of the importer; for a tax on his occupation is in effect, a tax on importation, as it must add to the price of the article, and be paid by the consumer, or by the importer himself, in the same manner as a direct duty on the article.

806. The general power of taxation is retained by the States without being abridged by the grant of a similar power to the Government of the Union; and is to be concurrently exercised by both Governments under their respective Constitutions; but from the paramount authority of the Federal Government, it may withdraw any subject of taxation from the action of State power.

807. As the unavoidable consequence of the supremacy which the Constitution has declared, the States are restrained, without any express prohibition, from any exercise of their taxing power, which

in its nature is incompatible with, or repugnant to, the constitutional Laws of the Union. .

808. As the States have no power by taxation, or otherwise, to retard, impede, burthen, or in any manner to control, the operation of constitutional Laws enacted by Congress to carry into execution the powers vested in the General Government, they cannot tax the Stock of the Bank of the United States, or the certificates issued by the Government for money borrowed on the credit of the United States; for the one is an instrument, and the others incidents of a power, essential to the fiscal operations of the -Union.

809. The other qualified prohibitions have their origin in the same general policy which absolutely forbids any State from entering into any Treaty, Alliance, or Confederation; and, from granting Letters of Marque and Reprisal; and they are supported by the same reasoning which establishes the propriety of confiding every thing relating to the power of declaring War, to the exclusive direction and control of the National Government.

810. Treaties of alliance, for purposes of Peace or War, of external political dependence, or general commercial privileges; Treaties of Confederation for mutual government, political co-operation, or the exercise of political sovereignty, or for conferring internal political jurisdiction, are absolutely prohibited to the States.

811. But compacts and agreements which apply to the mere private rights of sovereignty, such as questions of boundary between a State and a foreign province, or another State; interests in land situate within their respective boundaries, and other inter

nal regulations for the mutual accommodation of States bordering on each other, may be entered into by the respective States, with the consent of Congress.

812. A total interdiction of such agreements or Contracts, might have been attended with permanent inconvenience or public injury to the States; and the consent of Congress to their being entered into, is required to guard against every infringement of the National rights, which might be involved in them.

813. As the maintenance of an Army and Navy by a State in time of Peace might produce jealousies and alarm in neighbouring States, and in foreign Nations possessing provinces bordering on its territory, the States are prohibited therefrom, unless with the consent of the National Government. But as a State may be so situated in time of war, as to render a military force necessary to resist an invasion, of which the danger may be too imminent to admit of delay in organizing it, the States have a right to raise troops, and fit out fleets for its own safety in time of war, without obtaining the consent of Congress.

CHAPTER VI.

OF THE PROVISIONS CONTAINED IN THE CONSTITUTION, FOR GIVING EFFICACY TO THE POWERS VESTED IN THE GENERAL GOVERNMENT.

814. The last class of Powers enumerated in the Constitution, consists of the several provisions, by which efficacy is given to the rest; and the

I. Of these is, the "Power to make all Laws necessary and proper for carrying into execution the foregoing Powers."

815. This power would have resulted by necessary implication, from the act of establishing a National Government and vesting it with certain powers; as without the necessary and proper means of executing those Powers, the ends proposed by them could never be attained.

816. The plain import of the clause is, that Congress shall have all the incidental and instrumental powers necessary and proper to carry into execution their express powers; and it seems to have been inserted in the Constitution from abundant caution, as it neither enlarges nor restricts any power specifically granted, nor grants any new power; but is merely a declaration to remove all uncertainty as to whether the means of carrying the powers previously granted into execution, were included in the grant.

817. Whenever a question arises concerning the constitutionality of a particular power of Congress, the first inquiry is, whether the power be expressed in the Constitution; if it be, all doubt as to its existence, must be at once removed; but if it be not contained in terms, in the Constitution, the inquiry then is, whether it be properly an incident to an express power, and necessary to its execution.

818. The question then arises as to the true interpretation of the terms "necessary and proper,"-i. e. whether the word "necessary," is used in its closest and most intense meaning, so as to exclude all means except such as are absolutely and indispensably necessary, and without which the grant would be nugatory; or whether these terms allow to Congress a choice of the most convenient and appropriate means, amongst those which are calculated to effect the end.

819. The latter construction has been adopted by