Over alien enemies in time of war congress have also exercised the right of legislation, and the power appears to be generally conceded to them ; but it is more doubted whe ther they can exercise the same over alien friends, by an alien law similar to that of Great Britain. Such an act was passed in the year 1798, at a time when it was believed that danger was to be apprehended from the emissaries of the Directory of France (then a Republic). But this law, the duration of which was limited to two years, and was at the time very unpopular, was suffered to expire by its own li mitation, and has never since been reenacted.
Over the persons composing the army and navy of the United States, congress have undoubtedly a right to legis late, and as far as relates to their military duties this right is admitted to be exclusive ; they have even passed laws to exempt them from the jurisdiction of the states in civil cases ; but it is not understood that they can by law free hem from the consequences of a breach of the peace or violation of the criminal laws of the state in which they may reside at the time of the act committed.
Congress have also the power of exclusive legislation over their civil officers, as far as respects their official du ties ; they may likewise declare the privileges of their own members, and enforce them by their own authority.
III. Of legislative power founded on the subject matter. This class of legislative powers is the most numerous and the most diversified of all those that are vested in the con gress of the United States, and within the various circles of this jurisdiction, their authority extends over all persons and places within the American territory. Notwithstand ing all the pains that have been taken to define these seve ral powers by the constitution, a great many of them must be gathered by construction or inference from the context oldie whole or from particular parts of the instrument. Of these some arc exclusively granted to the federal legisla ture by express provisions in the constitution, others (though not so expressly given) yet appeal' from their very nature to be also exclusive, while others are vested in them concurrently with the legislatures of the several states. To discriminate correctly between the exclusive and the concurrent legislative powers of the federal and state governments is a matter of no small difficulty ; it is best to leave the decision of all these doubtful points to the competent authorities, whenever the questions shall come properly before them.
The legislative powers which the constitution expressly vests in the congress of the United States are the following : 1. To lay and collect taxes, duties, imposts and excises.
The exercise of this power is limited to the object of " paying the debts and providing for the common defence and general welfare of the United States ;" which seems to be rather the expression of the motives which induced the grant, than a restriction of the authority granted ; yet it is not impossible that cases may occur in which this clause may be restrictively construed.
This power is also modified, in as much as the same pa ragraph provides " that all duties, imposts and excises, shall be uniform throughout the United States." 2. To borrow money on the credit of the United States.
3. To regulate commerce with foreign nations, among the several states, and with the Indian tribes.
4. To establish an uniform rule of naturalization.
5. To make uniform laws on the subject of bankruptcies throughout the United States.
A general uniform bankrupt law was made by congress in the year 1800, which was limited in its duration to five years. Three years afterwards it was repealed, and has not been since revived ; though such a law is much wanted in the commercial towns.
6. To coin money, regulate its value, and that of foreign coins.
7. To fix the standard of weights and measures. Ills power has not yet been acted upon.
8. To provide for the punishment of counterfeiting the securities and current coin of the United States.
9. To establish post offices.
10. To establish post roads.
The construction of this last article has occasioned much discussion in and out of congress, and is not yet finally set tled. Some are of opinion that it gives to the federal le gislature the power of making new roads, others that it only authorises them to erect roads already made into post roads. The power of making military roads, for purposes of national defence, seems generally admitted without any restriction.
11. To promote the progress of science and useful arts, by securing, for limited times, to authors and inventors, the exclusive right to their respective writings and discove ries.