It remains, therefore, to consider the question of the measure of discretion in the exercise by Congress of the power to provide for the improvement of rivers and harbors, and also that of the legitimate responsibility of the Executive in the same relation.

In matters of legislation of the most unquestionable constitutionality it is always material to consider what amount of public money shall be appropriated for any particular object.  The same consideration applies with augmented force to a class of appropriations which are in their nature peculiarly prone to run to excess, and which, being made in the exercise of incidental powers, have intrinsic tendency to overstep the bounds of constitutionality.

If an appropriation for improving the navigability of a river or deepening or protecting a harbor have reference to military or naval purposes, then its rightfulness, whether in amount or in the objects to which it is applied, depends, manifestly, on the military or naval exigency; and the subject-matter affords its own measure of legislative discretion.  But if the appropriation for such an object have no distinct relation to the military or naval wants of the country, and is wholly, or even mainly, intended to promote the revenue from commerce, then the very vagueness of the proposed purpose of the expenditure constitutes a perpetual admonition of reserve and caution.  Through disregard of this it is undeniable that in many cases appropriations of this nature have been made unwisely, without accomplishing beneficial results commensurate with the cost, and sometimes for evil rather than good, independently of their dubious relation to the Constitution.

Among the radical changes of the course of legislation in these matters which, in my judgment, the public interest demands, one is a return to the primitive idea of Congress, which required in this class of public works, as in all others, a conveyance of the soil and a cession of the jurisdiction to the United States.  I think this condition ought never to have been waived in the case of any harbor improvement of a permanent nature, as where piers, jetties, sea walls, and other like works are to be constructed and maintained.  It would powerfully tend to counteract endeavors to obtain appropriations of a local character and chiefly calculated to promote individual interests.  The want of such a provision is the occasion of abuses in regard to existing works, exposing them to private encroachment without sufficient means of redress by law.  Indeed, the absence in such cases of a cession of jurisdiction has constituted one of the constitutional objections to appropriations of this class.  It is not easy to perceive any sufficient reason for requiring it in the case of arsenals or forts which does not equally apply to all other public works.  If to be constructed and maintained by Congress in the exercise of a constitutional power of appropriation, they should be brought within the jurisdiction of the United States.