Page:Joseph Story, Commentaries on the Constitution of the United States (1st ed, 1833, vol III).djvu/159

 CH. XXVI.] § 1270. For the same reason congress may authorize the laying out and making of a military road, and acquire a right over the soil for such purposes; and as incident thereto they have a power to keep the road in repair, and prevent all obstructions thereto. But in these, and the like cases, the general jurisdiction of the state over the soil, subject only to the rights of the United States, is not excluded. As, for example, in case of a military road; although a state cannot prevent repairs on the part of the United States, or authorize any obstructions of the road, its general jurisdiction remains untouched. It may punish all crimes committed on the road; and it retains in other respects its territorial sovereignty over it. The right of soil may still remain in the state, or in individuals, and the right to the easement only in the national government. There is a great distinction between the exercise of a power, excluding altogether state jurisdiction, and the exercise of a power, which leaves the state jurisdiction generally in force, and yet includes, on the part of the national government, a power to preserve, what it has created.

§ 1271. In all these, and other cases, in which the power of congress is asserted, it is so upon the general ground of its being an incidental power; and the course of reasoning, by which it is supported, is precisely the same, as that adopted in relation to other cases already considered. It is, for instance, admitted, that congress cannot authorize the making of a canal, except for some purpose of commerce among the states, or for some