be exclusive. But if, without any such reason for an implied or consequential exclusion, a particular power is delegated to Congress, it is, though not necessarily exclusive, necessarily supreme; and, of course, Congress may, if they please, prohibit any interference with their authority, as well by addition as by subtraction.1

§ 374. An instance of this is furnished by the post-office. Congress has not only "established post-offices," but given their establishment an entire monopoly of certain kinds of business, even punishing as a crime any participation in them, by virtue of State authority or otherwise.2 These principles are plain and practical, so far as they respect subjects that are single and indivisible. But when applied to subjects that are compound, involving particulars numerous and complicated, questions of more or less difficulty may arise. Take, for instance, the great subject of foreign commerce, - only one department of the whole commercial power. The Supreme Court have decided that it belongs to Congress exclusively. It includes particulars almost in

1 "It is obvious, that in those cases in which the United States may exercise the right of exclusive legislation, it will rest with Congress to determine whether the general government shall exercise the right of punishing exclusively, or leave the States at liberty to exercise their own discretion."- Houston v. Moore, 5 Wheat., 33, per Johnson, J.

2 This power is exercised by the single act of making the establishment. But from this has been inferred the power and duty of carrying the mail along the post-road, from one post-office to another. And from this implied power has again been inferred the right to punish those who steal letters from the post-office, or rob the mail."- Per Marshall, C. J., in McCulloch v. Maryland, 4 Wheat. R., 417.

numerable. Suppose Congress to have neglected the construction of a suitable lighthouse, breakwater, beacon, pier, or buoy, in some harbor within a State. It is a part of the power to regulate commerce. In what sense is it exclusive?

§ 375. Would it be unconstitutional for a man, interested in the navigation of the harbor, to set up a lantern to guide in his ship in a dark night; or even to induce his neighbors similarly situated, his insurance company, his town, city, or State, to join with him in defraying the expense of establishing and maintaining it? A standard of weights and measures for the country is also an exclusive national authority, not only as a part of commerce, but also from the extent of its operation; none but a national power being competent to it. But suppose the general government do nothing, -as they have heretofore done with this, and some other subjects delegated to them, may not a man have a uniform standard for himself? and may not a town, city, or State adopt the same, or a different one, for all who acknowledge their jurisdiction, so long as they interfere with no paramount law? Such is the condition of the law of weights and meaCongress, having all power over the subject, has never exercised it. Either the anterevolutionary law remains in force, or such laws as any of the States may have made are substituted, or there is none.

sures.

§ 376. The power "to provide for the punishment of counterfeiting the securities and current coin of the United States," though expressly conferred, is necessarily an incident to the power of making, regulating, or authorizing the originals so counterfeited, and doubtless extends to every thing authorized to be used as money or currency. "To define and punish piracies and felonies committed on the high seas, and offences against the law of nations," is another commercial subject, given to Congress by a distinct and special grant. Piracies and felonies, as well as other offences against the law of nations, may be committed on the high seas; but, because so committed, they may not be exclusively cognizable under that law. If committed from or on board of an American vessel, and by persons owing even a temporary allegiance to the country, they are directly subject to our own municipal law, and so punishable, independent of the law of nations. But, whether such acts are violations of either or both codes, they are alike subject to the jurisdiction of Congress, unless within the municipal jurisdiction of some other nation.

§ 377. The high seas, the locus in quo, and the law of nations, the rule violated, both enter into the nature of the offence, and constitute a part of it, and of course require defining for the same reason. The law of nations, which is a part of the common law,1 and like the rest of it 1 United States v. Smith, 5 Wheat. R., 161.

an unwritten law, is here made expressly a part of our Constitution, to be enforced by our government.1 The high seas may be defined by the common law, the civil law, or by the maritime law; but Congress are not bound by either: If the difference between piracy and robbery depends upon the line of high or low-water mark, or the state of the tide between them, Congress may define that difference. But the law of nations is a part of the law of the land, and to be executed as such by the proper departments, whether Congress define it or not. In this manner it may become the duty of the executive or the judiciary, or both, to find out what the law of nations is, and to punish the violation of it, even without any legislation.

§ 378. We have seen that the government, under the administration of Washington, undertook to know what were the duties of neutrals, by the law of nations, without any definition of Congress; and the judiciary were called upon and actually undertook to inquire, with a view to punish, the breach of them without legislative assistance. Both the executive and judiciary have had abundant occasion since to study the rights and duties of war, by the law of

1 "As a part of the Constitution, written or unwritten, of all governments, stand the laws of nations, necessarily, inevitably, from the relations which all communities bear to each other, and from the contingencies to which they are exposed. That being the case, and that unwritten law of nations being actually a part of our written law, we accept, as we must accept, all the consequences which follow from it.". Senator Fessenden's speech on the Freedmen's Bureau, in the Senate, Jan. 23, 1866.

nations, without a definition by the legislature; and have found authority to execute them, in the principles of the common law, as the houses of Congress have found authority to punish for contempts, without legislation. The different codes referred to, and adopted by our Constitution, as constituting a part of our system, have to be carried into effect by the executive and the judiciary, whenever circumstances requiring their application are brought respectively under their official cognizance. But all

"the laws necessary and proper” to render their execution adequate and effective have not been supplied by Congress. The decisions of the courts on this subject, and the clause of this section "to constitute tribunals inferior to the Supreme Court," will be considered when we come to Article III., on the judiciary.

§ 379. The only remaining topic of this section, directly connected with the commercial power, is "to establish post-offices and postroads." By the authority of two short words, "establish post-offices," the government have instituted an establishment employing more men, controlling more patronage, and collecting and disbursing more revenue, than sufficed, within a few years past, for the administration of the whole government. In 1860, there were 28,586 postmasters. Mails were annually transported more than eighty millions of miles; and the expenditures were $19,170,609. The estimates for