The next object of inquiry is whether the right to declare war includes the right to adopt and execute this system of improvement.  The objections to it are, I presume, not less conclusive than those which are applicable to the grant which we have just examined.

Under the last-mentioned grant a claim has been set up to as much of that system as relates to roads.  Under this it extends alike to roads and canals.

We must examine this grant by the same rules of construction that were applied to the preceding one.  The object was to take this power from the individual States and to vest it in the General Government.  This has been done in clear and explicit terms, first by granting the power to Congress, and secondly by prohibiting the exercise of it by the States.  “Congress shall have a right to declare war.”  This is the language of the grant.  If the right to adopt and execute this system of improvement is included in it, it must be by way of incident only, since there is nothing in the grant itself which bears any relation to roads and canals.  The following considerations, it is presumed, prove incontestably that this power has not been granted in that or any other manner.

The United States are exposed to invasion through the whole extent of their Atlantic coast by any European power with whom we might be engaged in war—­on the northern and northwestern frontier on the side of Canada by Great Britain, and on the southern by Spain or any power in alliance with her.  If internal improvements are to be carried to the full extent to which they may be useful for military purposes, the power as it exists must apply to all the roads of the Union, there being no limitation to it.  Wherever such improvements may facilitate the march of troops, the transportation of cannon, or otherwise aid the operations or mitigate the calamities of war along the coast or in any part of the interior they would be useful for military purposes, and might therefore be made.  The power following as an incident to another power can be measured as to its extent by reference only to the obvious extent of the power to which it is incidental.  So great a scope was, it is believed, never given to incidental power.

If it had been intended that the right to declare war should include all the powers necessary to maintain war, it would follow that nothing would have been done to impair the right or to restrain Congress from the exercise of any power which the exigencies of war might require.  The nature and extent of this exigency would mark the extent of the power granted, which should always be construed liberally, so as to be adequate to the end.  A right to raise money by taxes, duties, excises, and by loan, to raise and support armies and a navy, to provide for calling forth, arming, disciplining, and governing the militia when in the service of the United States, establishing fortifications and governing the troops stationed in them independently of the State authorities, and