Thus it appears that these provisions of law in effect prescribe conditions by which to determine whether any waters are public navigable waters, subject to the authority of the Federal Government.  The conditions include all waters, whether salt or fresh, and whether of sea, lake, or river, provided they be capable of navigation by vessels of a certain tonnage, and for commerce either between the United States and foreign countries or between any two or more of the States or Territories of the Union.  This excludes water wholly within any particular State, and not used as the means of commercial communication with any other State, and subject to be improved or obstructed at will by the State within which it may happen to be.

The constitutionality of these provisions of statute has been called in question.  Their constitutionality has been maintained, however, by repeated decisions of the Supreme Court of the United States, and they are therefore the law of the land by the concurrent act of the legislative, the executive, and the judicial departments of the Government.  Regarded as affording a criterion of what is navigable water, and as such subject to the maritime jurisdiction of the Supreme Court and of Congress, these acts are objectionable in this, that the rule of navigability is an arbitrary one, that Congress may repeal the present rule and adopt a new one, and that thus a legislative definition will be able to restrict or enlarge the limits of constitutional power.  Yet this variableness of standard seems inherent in the nature of things.  At any rate, neither the First Congress, composed of the statesmen of the era when the Constitution was adopted, nor any subsequent Congress has afforded us the means of attaining greater precision of construction as to this part of the Constitution.

This reflection may serve to relieve from undeserved reproach an idea of one of the greatest men of the Republic—­President Jackson.  He, seeking amid all the difficulties of the subject for some practical rule of action in regard to appropriations for the improvement of rivers and harbors, prescribed for his own official conduct the rule of confining such appropriations to “places below the ports of entry or delivery established by law.”  He saw clearly, as the authors of the above-mentioned acts of 1789 and 1845 did, that there is no inflexible natural line of discrimination between what is national and what local by means of which to determine absolutely and unerringly at what point on a river the jurisdiction of the United States shall end.  He perceived, and of course admitted, that the Constitution, while conferring on the General Government some power of action to render navigation safe and easy, had of necessity left to Congress much of discretion in this matter.  He confided in the patriotism of Congress to exercise that discretion wisely, not permitting himself to suppose it possible that a port of entry or delivery would ever be established by law for the express and only purpose of evading the Constitution.