The classic statement, however, of the scope of the "implied" powers of Congress is of course that made by Marshall in the opinion which he rendered in McCulloch v. Maryland.7 In that great case, the Chief Justice says: "It may with great reason be contended, that a government, entrusted with such ample powers [as is the United States] on the due execution of which the happiness and prosperity of the Nation so vitally depends, must be entrusted with ample means for their execution. The power being given, it is the interest of the Nation to facilitate its execution. It can never be their interest, and cannot be presumed to have been their intention, to stay and embarrass its execution by withholding the most appropriate means."

The determination of what are appropriate means must, Marshall goes on to declare, belong to the government which is to employ them. "The government which has a right to do an act, and has imposed on it the duty of performing that act," he says, " must, according to the dictates of reason, be allowed to select the means."

To the argument that a selected means must be an indispensable as well as a proper one, Marshall replies: "Is it true that this is the sense in which the word 'necessary' is always used? Does it always import an absolute physical necessity, so strong that one thing, to which another may be termed necessary, cannot exist without that other? We think it does not. If reference be had to its use, in the common affairs of the world, or in approved authors, we find that it frequently imports no more than that one thing is convenient or useful, or essential to another."

Applying this interpretation of the word to its use in the Constitution the opinion declares:

7 4 Wh. 316; 4 L. ed. 579.

"The subject is the execution of those great powers on which the welfare of a nation essentially depends. It must have been the intention of those who gave these powers, to insure, as far as human prudence could insure, their beneficial execution. This could not be done by confiding the choice of means to such narrow limits as not to leave it in the power of Congress to adopt any which might be appropriate, and which were conducive to the end. This provision is made in a constitution intended to endure for ages to come, and, consequently, to be adapted to the various crises of human affairs. To have prescribed the means by which government should, in all future time, execute its powers, would have been to change, entirely, the character of the instrument, and give it the properties of a legal code. It would have been an unwise attempt to provide, by immutable rules, for exigencies which, if foreseen at all, must have been seen dimly, and which can be best provided for as they occur. To have declared that the best means shall not be used, but those alone without which the power given would be nugatory, would have been to deprive the legislature of the capacity to avail itself of experience, to exercise its reason, and to accommodate its legislation to circumstances. If we apply this principle of construction to any of the powers of the government, we shall find it so pernicious in its operation that we shall be compelled to discard it."

In conclusion of this point, the Chief Justice says: "The result of the most careful and attentive consideration bestowed upon this clause is, that if it does not enlarge, it cannot be construed to restrain the powers of Congress, or to impair the right of the legislature to exercise its best judgment in the selection of measures to carry into execution the constitutional powers of the government. If no other motive for its insertion can be suggested, a sufficient one is found in the desire to remove all doubts respecting the right to legislate on that vast mass of incidental powers which must be involved in the Constitution, if that instrument be not a splendid bauble. We admit, as all must admit, that the powers of the government are limited, and that its limits are not to be transcended. But we think the sound construction of the Constitution must allow to the national legislature that discretion, with respect to the means by which the powers it confers are to be carried into execution, which will enable that body to perform the high duties assigned to it, in the manner most beneficial to the people. Let the end be legitimate, let it be within the scope of the Constitution, and all means which are appropriate, which are plainly adapted to that end, which are not prohibited, but consistent with the letter and spirit of the Constitution, are constitutional."

Reviewing the effect of this decision, it is seen that the words "and proper" as used in the phrase "necessary and proper" are construed not as declaring that a means selected by Congress shall be proper as well as necessary - that is, indispensable - for carrying into effect a specified power, but as qualifying and extending the force of "necessary" so as to render constitutional the selection of any means that may be appropriate, that is, may in any way assist the General Government in the exercise of its constitutional functions. It need not be said, of course, that the question as to whether or not the particular means selected is the best possible means that might have been adopted, is one for Congress to answer. All that the courts have to consider in passing upon its constitutionality is as to whether it is calculated in any appreciable degree to advance the constitutional end involved.

One further fact regarding the implied powers of Congress is to be noticed. This is that a power employed as incidental to the exercise of an express power may be used free from the limitation under which it would rest if exercised as an express power. Thus, in Veazie Bank v. Fenno8 and Head Money Cases9 the Supreme Court decided that the power of taxation when used simply as a means for regulating commerce and currency, is not subject to the constitutional limitations under which it would rest if exercised for the purpose of raising a revenue. In the Head Money-Cases the court declared, relative to a per capita tax levied by Congress upon persons, not citizens of the United States, coming to this country: "If this is an expedient regulation of commerce by Congress, and the end to be obtained is one falling within the power, the act is not void, because, within a loose-and more extended sense than was used in the Constitution,. it is called a tax. In the case of Veazie Bank v. Fenno, the enormous tax of ten per cent. per annum on the circulation of state banks, which was designed, and did have the effect, to drive all such circulation out of existence, was upheld because it was a means properly adopted by Congress to protect the currency which it had created. ... It was not subject, therefore, to the rules which would invalidate an ordinary tax pure and simple."

8 8 Wall. 533: 19 L. ed. 482.

9 112 U. S. 580; 5 Sup. Ct. Rep. 247; 28 L. ed. 798.